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1
by brian
clean slate |
1 |
drop table if exists t1,t2,t3;
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2 |
create table t1 (a int not null,b int not null, primary key (a)) engine=heap comment="testing heaps" avg_row_length=100 min_rows=1 max_rows=100;
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3 |
insert into t1 values(1,1),(2,2),(3,3),(4,4);
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4 |
delete from t1 where a=1 or a=0;
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5 |
show keys from t1;
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6 |
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_Comment
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7 |
t1 0 PRIMARY 1 a NULL 3 NULL NULL HASH
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8 |
select * from t1;
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9 |
a b
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10 |
2 2
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3 3
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4 4
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13 |
select * from t1 where a=4;
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a b
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4 4
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16 |
update t1 set b=5 where a=4;
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17 |
update t1 set b=b+1 where a>=3;
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18 |
replace t1 values (3,3);
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19 |
select * from t1;
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20 |
a b
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21 |
2 2
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22 |
3 3
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4 6
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24 |
alter table t1 add c int not null, add key (c,a);
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25 |
drop table t1;
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26 |
create table t1 (a int not null,b int not null, primary key (a)) engine=memory comment="testing heaps";
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27 |
insert into t1 values(1,1),(2,2),(3,3),(4,4);
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28 |
delete from t1 where a > 0;
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29 |
select * from t1;
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30 |
a b
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31 |
drop table t1;
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32 |
create table t1 (a int not null,b int not null, primary key (a)) engine=heap comment="testing heaps";
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33 |
insert into t1 values(1,1),(2,2),(3,3),(4,4);
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34 |
alter table t1 modify a int not null auto_increment, engine=myisam, comment="new myisam table";
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35 |
select * from t1;
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36 |
a b
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37 |
1 1
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38 |
2 2
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3 3
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4 4
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41 |
drop table t1;
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42 |
create table t1 (a int not null) engine=heap;
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43 |
insert into t1 values (869751),(736494),(226312),(802616),(728912);
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44 |
select * from t1 where a > 736494;
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45 |
a
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46 |
869751
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47 |
802616
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48 |
alter table t1 add unique uniq_id(a);
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49 |
select * from t1 where a > 736494;
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50 |
a
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51 |
869751
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52 |
802616
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53 |
select * from t1 where a = 736494;
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54 |
a
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55 |
736494
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56 |
select * from t1 where a=869751 or a=736494;
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57 |
a
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58 |
736494
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59 |
869751
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60 |
select * from t1 where a in (869751,736494,226312,802616);
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61 |
a
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62 |
226312
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63 |
736494
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64 |
802616
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65 |
869751
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alter table t1 engine=myisam;
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explain select * from t1 where a in (869751,736494,226312,802616);
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68 |
id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range uniq_id uniq_id 4 NULL 4 Using where; Using index
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70 |
drop table t1;
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create table t1 (x int not null, y int not null, key x (x), unique y (y))
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engine=heap;
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insert into t1 values (1,1),(2,2),(1,3),(2,4),(2,5),(2,6);
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74 |
select * from t1 where x=1;
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x y
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1 3
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1 1
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select * from t1,t1 as t2 where t1.x=t2.y;
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x y x y
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1 1 1 1
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2 2 2 2
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1 3 1 1
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2 4 2 2
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2 5 2 2
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2 6 2 2
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explain select * from t1,t1 as t2 where t1.x=t2.y;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL x NULL NULL NULL 6
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1 SIMPLE t2 eq_ref y y 4 test.t1.x 1
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90 |
drop table t1;
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91 |
create table t1 (a int) engine=heap;
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92 |
insert into t1 values(1);
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93 |
select max(a) from t1;
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94 |
max(a)
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95 |
1
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96 |
drop table t1;
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CREATE TABLE t1 ( a int not null default 0, b int not null default 0, key(a), key(b) ) ENGINE=HEAP;
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98 |
insert into t1 values(1,1),(1,2),(2,3),(1,3),(1,4),(1,5),(1,6);
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99 |
select * from t1 where a=1;
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a b
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1 6
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1 5
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1 4
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1 3
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1 2
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1 1
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107 |
insert into t1 values(1,1),(1,2),(2,3),(1,3),(1,4),(1,5),(1,6);
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108 |
select * from t1 where a=1;
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109 |
a b
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110 |
1 6
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1 5
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112 |
1 4
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113 |
1 3
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114 |
1 2
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115 |
1 1
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116 |
1 6
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117 |
1 5
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118 |
1 4
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119 |
1 3
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120 |
1 2
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121 |
1 1
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122 |
drop table t1;
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123 |
create table t1 (id int unsigned not null, primary key (id)) engine=HEAP;
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124 |
insert into t1 values(1);
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125 |
select max(id) from t1;
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126 |
max(id)
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127 |
1
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128 |
insert into t1 values(2);
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129 |
select max(id) from t1;
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130 |
max(id)
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131 |
2
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132 |
replace into t1 values(1);
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133 |
drop table t1;
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134 |
create table t1 (n int) engine=heap;
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135 |
drop table t1;
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136 |
create table t1 (n int) engine=heap;
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137 |
drop table if exists t1;
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138 |
CREATE table t1(f1 int not null,f2 char(20) not
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null,index(f2)) engine=heap;
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140 |
INSERT into t1 set f1=12,f2="bill";
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141 |
INSERT into t1 set f1=13,f2="bill";
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142 |
INSERT into t1 set f1=14,f2="bill";
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143 |
INSERT into t1 set f1=15,f2="bill";
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144 |
INSERT into t1 set f1=16,f2="ted";
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145 |
INSERT into t1 set f1=12,f2="ted";
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146 |
INSERT into t1 set f1=12,f2="ted";
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147 |
INSERT into t1 set f1=12,f2="ted";
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148 |
INSERT into t1 set f1=12,f2="ted";
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149 |
delete from t1 where f2="bill";
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150 |
select * from t1;
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151 |
f1 f2
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152 |
16 ted
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153 |
12 ted
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154 |
12 ted
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155 |
12 ted
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156 |
12 ted
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157 |
drop table t1;
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158 |
create table t1 (btn char(10) not null, key(btn)) engine=heap;
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159 |
insert into t1 values ("hello"),("hello"),("hello"),("hello"),("hello"),("a"),("b"),("c"),("d"),("e"),("f"),("g"),("h"),("i");
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160 |
explain select * from t1 where btn like "q%";
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161 |
id select_type table type possible_keys key key_len ref rows Extra
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162 |
1 SIMPLE t1 ALL btn NULL NULL NULL 14 Using where
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163 |
select * from t1 where btn like "q%";
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164 |
btn
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165 |
alter table t1 add column new_col char(1) not null, add key (btn,new_col), drop key btn;
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166 |
update t1 set new_col=left(btn,1);
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167 |
explain select * from t1 where btn="a";
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168 |
id select_type table type possible_keys key key_len ref rows Extra
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169 |
1 SIMPLE t1 ALL btn NULL NULL NULL 14 Using where
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170 |
explain select * from t1 where btn="a" and new_col="a";
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171 |
id select_type table type possible_keys key key_len ref rows Extra
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172 |
1 SIMPLE t1 ref btn btn 11 const,const 2 Using where
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173 |
drop table t1;
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174 |
CREATE TABLE t1 (
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a int default NULL,
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176 |
b int default NULL,
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177 |
KEY a (a),
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178 |
UNIQUE b (b)
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) engine=heap;
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180 |
INSERT INTO t1 VALUES (NULL,99),(99,NULL),(1,1),(2,2),(1,3);
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181 |
SELECT * FROM t1 WHERE a=NULL;
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182 |
a b
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183 |
explain SELECT * FROM t1 WHERE a IS NULL;
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184 |
id select_type table type possible_keys key key_len ref rows Extra
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185 |
1 SIMPLE t1 ref a a 5 const 2 Using where
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186 |
SELECT * FROM t1 WHERE a<=>NULL;
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187 |
a b
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188 |
NULL 99
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189 |
SELECT * FROM t1 WHERE b=NULL;
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190 |
a b
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191 |
explain SELECT * FROM t1 WHERE b IS NULL;
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192 |
id select_type table type possible_keys key key_len ref rows Extra
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193 |
1 SIMPLE t1 ref b b 5 const 1 Using where
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194 |
SELECT * FROM t1 WHERE b<=>NULL;
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195 |
a b
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196 |
99 NULL
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197 |
INSERT INTO t1 VALUES (1,3);
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198 |
ERROR 23000: Duplicate entry '3' for key 'b'
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199 |
DROP TABLE t1;
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200 |
CREATE TABLE t1 (
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201 |
a int default NULL,
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202 |
key a (a)
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203 |
) ENGINE=HEAP;
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204 |
INSERT INTO t1 VALUES (10), (10), (10);
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205 |
EXPLAIN SELECT * FROM t1 WHERE a=10;
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206 |
id select_type table type possible_keys key key_len ref rows Extra
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207 |
1 SIMPLE t1 ref a a 5 const 3
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208 |
SELECT * FROM t1 WHERE a=10;
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209 |
a
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210 |
10
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211 |
10
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212 |
10
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213 |
DROP TABLE t1;
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214 |
CREATE TABLE t1 (a int not null, primary key(a)) engine=heap;
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215 |
INSERT into t1 values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11);
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216 |
DELETE from t1 where a < 100;
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217 |
SELECT * from t1;
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218 |
a
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219 |
DROP TABLE t1;
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220 |
CREATE TABLE `job_titles` (
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221 |
`job_title_id` int(6) unsigned NOT NULL default '0',
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222 |
`job_title` char(18) NOT NULL default '',
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223 |
PRIMARY KEY (`job_title_id`),
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224 |
UNIQUE KEY `job_title_id` (`job_title_id`,`job_title`)
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225 |
) ENGINE=HEAP;
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226 |
SELECT MAX(job_title_id) FROM job_titles;
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227 |
MAX(job_title_id)
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228 |
NULL
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229 |
DROP TABLE job_titles;
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230 |
CREATE TABLE t1 (a INT NOT NULL, B INT, KEY(B)) ENGINE=HEAP;
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231 |
INSERT INTO t1 VALUES(1,1), (1,NULL);
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232 |
SELECT * FROM t1 WHERE B is not null;
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233 |
a B
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234 |
1 1
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235 |
DROP TABLE t1;
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236 |
CREATE TABLE t1 (pseudo char(35) PRIMARY KEY, date int(10) unsigned NOT NULL) ENGINE=HEAP;
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237 |
INSERT INTO t1 VALUES ('massecot',1101106491),('altec',1101106492),('stitch+',1101106304),('Seb Corgan',1101106305),('beerfilou',1101106263),('flaker',1101106529),('joce8',5),('M4vrick',1101106418),('gabay008',1101106525),('Vamp irX',1101106291),('ZoomZip',1101106546),('rip666',1101106502),('CBP ',1101106397),('guezpard',1101106496);
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238 |
DELETE FROM t1 WHERE date<1101106546;
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239 |
SELECT * FROM t1;
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240 |
pseudo date
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241 |
ZoomZip 1101106546
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242 |
DROP TABLE t1;
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243 |
create table t1(a char(2)) engine=memory;
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244 |
insert into t1 values (NULL), (NULL);
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245 |
delete from t1 where a is null;
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246 |
insert into t1 values ('2'), ('3');
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247 |
select * from t1;
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248 |
a
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249 |
3
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250 |
2
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251 |
drop table t1;
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252 |
set storage_engine=HEAP;
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253 |
create table t1 (v varchar(10), c char(10), t varchar(50));
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254 |
insert into t1 values('+ ', '+ ', '+ ');
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255 |
set @a=repeat(' ',20);
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256 |
insert into t1 values (concat('+',@a),concat('+',@a),concat('+',@a));
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257 |
Warnings:
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258 |
Note 1265 Data truncated for column 'v' at row 1
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259 |
Note 1265 Data truncated for column 'c' at row 1
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260 |
select concat('*',v,'*',c,'*',t,'*') from t1;
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261 |
concat('*',v,'*',c,'*',t,'*')
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262 |
*+ *+*+ *
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263 |
*+ *+*+ *
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264 |
show create table t1;
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265 |
Table Create Table
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266 |
t1 CREATE TABLE `t1` (
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267 |
`v` varchar(10) DEFAULT NULL,
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268 |
`c` char(10) DEFAULT NULL,
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269 |
`t` varchar(50) DEFAULT NULL
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270 |
) ENGINE=MEMORY DEFAULT CHARSET=latin1
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271 |
create table t2 like t1;
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272 |
show create table t2;
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273 |
Table Create Table
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274 |
t2 CREATE TABLE `t2` (
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275 |
`v` varchar(10) DEFAULT NULL,
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276 |
`c` char(10) DEFAULT NULL,
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277 |
`t` varchar(50) DEFAULT NULL
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278 |
) ENGINE=MEMORY DEFAULT CHARSET=latin1
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279 |
create table t3 select * from t1;
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280 |
show create table t3;
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281 |
Table Create Table
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282 |
t3 CREATE TABLE `t3` (
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283 |
`v` varchar(10) DEFAULT NULL,
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284 |
`c` char(10) DEFAULT NULL,
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285 |
`t` varchar(50) DEFAULT NULL
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286 |
) ENGINE=MEMORY DEFAULT CHARSET=latin1
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287 |
alter table t1 modify c varchar(10);
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288 |
show create table t1;
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289 |
Table Create Table
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290 |
t1 CREATE TABLE `t1` (
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291 |
`v` varchar(10) DEFAULT NULL,
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292 |
`c` varchar(10) DEFAULT NULL,
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293 |
`t` varchar(50) DEFAULT NULL
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294 |
) ENGINE=MEMORY DEFAULT CHARSET=latin1
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295 |
alter table t1 modify v char(10);
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296 |
show create table t1;
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297 |
Table Create Table
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298 |
t1 CREATE TABLE `t1` (
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299 |
`v` char(10) DEFAULT NULL,
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300 |
`c` varchar(10) DEFAULT NULL,
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301 |
`t` varchar(50) DEFAULT NULL
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302 |
) ENGINE=MEMORY DEFAULT CHARSET=latin1
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303 |
alter table t1 modify t varchar(10);
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304 |
Warnings:
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305 |
Warning 1265 Data truncated for column 't' at row 2
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306 |
show create table t1;
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307 |
Table Create Table
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308 |
t1 CREATE TABLE `t1` (
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309 |
`v` char(10) DEFAULT NULL,
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310 |
`c` varchar(10) DEFAULT NULL,
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311 |
`t` varchar(10) DEFAULT NULL
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312 |
) ENGINE=MEMORY DEFAULT CHARSET=latin1
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313 |
select concat('*',v,'*',c,'*',t,'*') from t1;
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314 |
concat('*',v,'*',c,'*',t,'*')
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315 |
*+*+*+ *
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316 |
*+*+*+ *
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317 |
drop table t1,t2,t3;
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318 |
create table t1 (v varchar(10), c char(10), t varchar(50), key(v), key(c), key(t(10)));
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319 |
show create table t1;
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320 |
Table Create Table
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321 |
t1 CREATE TABLE `t1` (
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322 |
`v` varchar(10) DEFAULT NULL,
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323 |
`c` char(10) DEFAULT NULL,
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324 |
`t` varchar(50) DEFAULT NULL,
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325 |
KEY `v` (`v`),
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326 |
KEY `c` (`c`),
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327 |
KEY `t` (`t`(10))
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328 |
) ENGINE=MEMORY DEFAULT CHARSET=latin1
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329 |
select count(*) from t1;
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330 |
count(*)
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331 |
270
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332 |
insert into t1 values(concat('a',char(1)),concat('a',char(1)),concat('a',char(1)));
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333 |
select count(*) from t1 where v='a';
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334 |
count(*)
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335 |
10
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336 |
select count(*) from t1 where c='a';
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337 |
count(*)
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338 |
10
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339 |
select count(*) from t1 where t='a';
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340 |
count(*)
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341 |
10
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342 |
select count(*) from t1 where v='a ';
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343 |
count(*)
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344 |
10
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345 |
select count(*) from t1 where c='a ';
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346 |
count(*)
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347 |
10
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348 |
select count(*) from t1 where t='a ';
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349 |
count(*)
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350 |
10
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351 |
select count(*) from t1 where v between 'a' and 'a ';
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352 |
count(*)
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353 |
10
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354 |
select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
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355 |
count(*)
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356 |
10
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357 |
select count(*) from t1 where v like 'a%';
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358 |
count(*)
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359 |
11
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360 |
select count(*) from t1 where c like 'a%';
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361 |
count(*)
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362 |
11
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363 |
select count(*) from t1 where t like 'a%';
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364 |
count(*)
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365 |
11
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366 |
select count(*) from t1 where v like 'a %';
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367 |
count(*)
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368 |
9
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369 |
explain select count(*) from t1 where v='a ';
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370 |
id select_type table type possible_keys key key_len ref rows Extra
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371 |
1 SIMPLE t1 ref v v 13 const 10 Using where
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372 |
explain select count(*) from t1 where c='a ';
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373 |
id select_type table type possible_keys key key_len ref rows Extra
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374 |
1 SIMPLE t1 ref c c 11 const 10 Using where
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375 |
explain select count(*) from t1 where t='a ';
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376 |
id select_type table type possible_keys key key_len ref rows Extra
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377 |
1 SIMPLE t1 ref t t 13 const 10 Using where
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|
378 |
explain select count(*) from t1 where v like 'a%';
|
|
379 |
id select_type table type possible_keys key key_len ref rows Extra
|
|
380 |
1 SIMPLE t1 ALL v NULL NULL NULL 271 Using where
|
|
381 |
explain select count(*) from t1 where v between 'a' and 'a ';
|
|
382 |
id select_type table type possible_keys key key_len ref rows Extra
|
|
383 |
1 SIMPLE t1 ref v v 13 const 10 Using where
|
|
384 |
explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
|
|
385 |
id select_type table type possible_keys key key_len ref rows Extra
|
|
386 |
1 SIMPLE t1 ref v v 13 const 10 Using where
|
|
387 |
alter table t1 add unique(v);
|
|
388 |
ERROR 23000: Duplicate entry '{ ' for key 'v_2'
|
|
389 |
select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a' order by length(concat('*',v,'*',c,'*',t,'*'));
|
|
390 |
qq
|
|
391 |
*a*a*a*
|
|
392 |
*a *a*a *
|
|
393 |
*a *a*a *
|
|
394 |
*a *a*a *
|
|
395 |
*a *a*a *
|
|
396 |
*a *a*a *
|
|
397 |
*a *a*a *
|
|
398 |
*a *a*a *
|
|
399 |
*a *a*a *
|
|
400 |
*a *a*a *
|
|
401 |
explain select * from t1 where v='a';
|
|
402 |
id select_type table type possible_keys key key_len ref rows Extra
|
|
403 |
1 SIMPLE t1 ref v v 13 const 10 Using where
|
|
404 |
select v,count(*) from t1 group by v limit 10;
|
|
405 |
v count(*)
|
|
406 |
a 1
|
|
407 |
a 10
|
|
408 |
b 10
|
|
409 |
c 10
|
|
410 |
d 10
|
|
411 |
e 10
|
|
412 |
f 10
|
|
413 |
g 10
|
|
414 |
h 10
|
|
415 |
i 10
|
|
416 |
select v,count(t) from t1 group by v limit 10;
|
|
417 |
v count(t)
|
|
418 |
a 1
|
|
419 |
a 10
|
|
420 |
b 10
|
|
421 |
c 10
|
|
422 |
d 10
|
|
423 |
e 10
|
|
424 |
f 10
|
|
425 |
g 10
|
|
426 |
h 10
|
|
427 |
i 10
|
|
428 |
select v,count(c) from t1 group by v limit 10;
|
|
429 |
v count(c)
|
|
430 |
a 1
|
|
431 |
a 10
|
|
432 |
b 10
|
|
433 |
c 10
|
|
434 |
d 10
|
|
435 |
e 10
|
|
436 |
f 10
|
|
437 |
g 10
|
|
438 |
h 10
|
|
439 |
i 10
|
|
440 |
select sql_big_result trim(v),count(t) from t1 group by v limit 10;
|
|
441 |
trim(v) count(t)
|
|
442 |
a 1
|
|
443 |
a 10
|
|
444 |
b 10
|
|
445 |
c 10
|
|
446 |
d 10
|
|
447 |
e 10
|
|
448 |
f 10
|
|
449 |
g 10
|
|
450 |
h 10
|
|
451 |
i 10
|
|
452 |
select sql_big_result trim(v),count(c) from t1 group by v limit 10;
|
|
453 |
trim(v) count(c)
|
|
454 |
a 1
|
|
455 |
a 10
|
|
456 |
b 10
|
|
457 |
c 10
|
|
458 |
d 10
|
|
459 |
e 10
|
|
460 |
f 10
|
|
461 |
g 10
|
|
462 |
h 10
|
|
463 |
i 10
|
|
464 |
select c,count(*) from t1 group by c limit 10;
|
|
465 |
c count(*)
|
|
466 |
a 1
|
|
467 |
a 10
|
|
468 |
b 10
|
|
469 |
c 10
|
|
470 |
d 10
|
|
471 |
e 10
|
|
472 |
f 10
|
|
473 |
g 10
|
|
474 |
h 10
|
|
475 |
i 10
|
|
476 |
select c,count(t) from t1 group by c limit 10;
|
|
477 |
c count(t)
|
|
478 |
a 1
|
|
479 |
a 10
|
|
480 |
b 10
|
|
481 |
c 10
|
|
482 |
d 10
|
|
483 |
e 10
|
|
484 |
f 10
|
|
485 |
g 10
|
|
486 |
h 10
|
|
487 |
i 10
|
|
488 |
select sql_big_result c,count(t) from t1 group by c limit 10;
|
|
489 |
c count(t)
|
|
490 |
a 1
|
|
491 |
a 10
|
|
492 |
b 10
|
|
493 |
c 10
|
|
494 |
d 10
|
|
495 |
e 10
|
|
496 |
f 10
|
|
497 |
g 10
|
|
498 |
h 10
|
|
499 |
i 10
|
|
500 |
select t,count(*) from t1 group by t limit 10;
|
|
501 |
t count(*)
|
|
502 |
a 1
|
|
503 |
a 10
|
|
504 |
b 10
|
|
505 |
c 10
|
|
506 |
d 10
|
|
507 |
e 10
|
|
508 |
f 10
|
|
509 |
g 10
|
|
510 |
h 10
|
|
511 |
i 10
|
|
512 |
select t,count(t) from t1 group by t limit 10;
|
|
513 |
t count(t)
|
|
514 |
a 1
|
|
515 |
a 10
|
|
516 |
b 10
|
|
517 |
c 10
|
|
518 |
d 10
|
|
519 |
e 10
|
|
520 |
f 10
|
|
521 |
g 10
|
|
522 |
h 10
|
|
523 |
i 10
|
|
524 |
select sql_big_result trim(t),count(t) from t1 group by t limit 10;
|
|
525 |
trim(t) count(t)
|
|
526 |
a 1
|
|
527 |
a 10
|
|
528 |
b 10
|
|
529 |
c 10
|
|
530 |
d 10
|
|
531 |
e 10
|
|
532 |
f 10
|
|
533 |
g 10
|
|
534 |
h 10
|
|
535 |
i 10
|
|
536 |
drop table t1;
|
|
537 |
create table t1 (a char(10), unique (a));
|
|
538 |
insert into t1 values ('a');
|
|
539 |
insert into t1 values ('a ');
|
|
540 |
ERROR 23000: Duplicate entry 'a' for key 'a'
|
|
541 |
alter table t1 modify a varchar(10);
|
|
542 |
insert into t1 values ('a '),('a '),('a '),('a ');
|
|
543 |
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
|
544 |
insert into t1 values ('a ');
|
|
545 |
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
|
546 |
insert into t1 values ('a ');
|
|
547 |
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
|
548 |
insert into t1 values ('a ');
|
|
549 |
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
|
550 |
update t1 set a='a ' where a like 'a ';
|
|
551 |
update t1 set a='a ' where a like 'a ';
|
|
552 |
drop table t1;
|
|
553 |
create table t1 (v varchar(10), c char(10), t varchar(50), key using btree (v), key using btree (c), key using btree (t(10)));
|
|
554 |
show create table t1;
|
|
555 |
Table Create Table
|
|
556 |
t1 CREATE TABLE `t1` (
|
|
557 |
`v` varchar(10) DEFAULT NULL,
|
|
558 |
`c` char(10) DEFAULT NULL,
|
|
559 |
`t` varchar(50) DEFAULT NULL,
|
|
560 |
KEY `v` (`v`) USING BTREE,
|
|
561 |
KEY `c` (`c`) USING BTREE,
|
|
562 |
KEY `t` (`t`(10)) USING BTREE
|
|
563 |
) ENGINE=MEMORY DEFAULT CHARSET=latin1
|
|
564 |
select count(*) from t1;
|
|
565 |
count(*)
|
|
566 |
270
|
|
567 |
insert into t1 values(concat('a',char(1)),concat('a',char(1)),concat('a',char(1)));
|
|
568 |
select count(*) from t1 where v='a';
|
|
569 |
count(*)
|
|
570 |
10
|
|
571 |
select count(*) from t1 where c='a';
|
|
572 |
count(*)
|
|
573 |
10
|
|
574 |
select count(*) from t1 where t='a';
|
|
575 |
count(*)
|
|
576 |
10
|
|
577 |
select count(*) from t1 where v='a ';
|
|
578 |
count(*)
|
|
579 |
10
|
|
580 |
select count(*) from t1 where c='a ';
|
|
581 |
count(*)
|
|
582 |
10
|
|
583 |
select count(*) from t1 where t='a ';
|
|
584 |
count(*)
|
|
585 |
10
|
|
586 |
select count(*) from t1 where v between 'a' and 'a ';
|
|
587 |
count(*)
|
|
588 |
10
|
|
589 |
select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
|
|
590 |
count(*)
|
|
591 |
10
|
|
592 |
explain select count(*) from t1 where v='a ';
|
|
593 |
id select_type table type possible_keys key key_len ref rows Extra
|
|
594 |
1 SIMPLE t1 ref v v 13 const # Using where
|
|
595 |
explain select count(*) from t1 where c='a ';
|
|
596 |
id select_type table type possible_keys key key_len ref rows Extra
|
|
597 |
1 SIMPLE t1 ref c c 11 const # Using where
|
|
598 |
explain select count(*) from t1 where t='a ';
|
|
599 |
id select_type table type possible_keys key key_len ref rows Extra
|
|
600 |
1 SIMPLE t1 ref t t 13 const # Using where
|
|
601 |
explain select count(*) from t1 where v like 'a%';
|
|
602 |
id select_type table type possible_keys key key_len ref rows Extra
|
|
603 |
1 SIMPLE t1 range v v 13 NULL # Using where
|
|
604 |
explain select count(*) from t1 where v between 'a' and 'a ';
|
|
605 |
id select_type table type possible_keys key key_len ref rows Extra
|
|
606 |
1 SIMPLE t1 ref v v 13 const # Using where
|
|
607 |
explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
|
|
608 |
id select_type table type possible_keys key key_len ref rows Extra
|
|
609 |
1 SIMPLE t1 ref v v 13 const # Using where
|
|
610 |
alter table t1 add unique(v);
|
|
611 |
ERROR 23000: Duplicate entry '{ ' for key 'v_2'
|
|
612 |
select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a' order by length(concat('*',v,'*',c,'*',t,'*'));
|
|
613 |
qq
|
|
614 |
*a*a*a*
|
|
615 |
*a *a*a *
|
|
616 |
*a *a*a *
|
|
617 |
*a *a*a *
|
|
618 |
*a *a*a *
|
|
619 |
*a *a*a *
|
|
620 |
*a *a*a *
|
|
621 |
*a *a*a *
|
|
622 |
*a *a*a *
|
|
623 |
*a *a*a *
|
|
624 |
explain select * from t1 where v='a';
|
|
625 |
id select_type table type possible_keys key key_len ref rows Extra
|
|
626 |
1 SIMPLE t1 ref v v 13 const # Using where
|
|
627 |
drop table t1;
|
|
628 |
create table t1 (a char(10), unique using btree (a)) engine=heap;
|
|
629 |
insert into t1 values ('a');
|
|
630 |
insert into t1 values ('a ');
|
|
631 |
ERROR 23000: Duplicate entry 'a' for key 'a'
|
|
632 |
alter table t1 modify a varchar(10);
|
|
633 |
insert into t1 values ('a '),('a '),('a '),('a ');
|
|
634 |
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
|
635 |
insert into t1 values ('a ');
|
|
636 |
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
|
637 |
insert into t1 values ('a ');
|
|
638 |
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
|
639 |
insert into t1 values ('a ');
|
|
640 |
ERROR 23000: Duplicate entry 'a ' for key 'a'
|
|
641 |
update t1 set a='a ' where a like 'a ';
|
|
642 |
update t1 set a='a ' where a like 'a ';
|
|
643 |
drop table t1;
|
|
644 |
create table t1 (v varchar(10), c char(10), t varchar(50), key(v(5)), key(c(5)), key(t(5)));
|
|
645 |
show create table t1;
|
|
646 |
Table Create Table
|
|
647 |
t1 CREATE TABLE `t1` (
|
|
648 |
`v` varchar(10) DEFAULT NULL,
|
|
649 |
`c` char(10) DEFAULT NULL,
|
|
650 |
`t` varchar(50) DEFAULT NULL,
|
|
651 |
KEY `v` (`v`(5)),
|
|
652 |
KEY `c` (`c`(5)),
|
|
653 |
KEY `t` (`t`(5))
|
|
654 |
) ENGINE=MEMORY DEFAULT CHARSET=latin1
|
|
655 |
drop table t1;
|
|
656 |
create table t1 (v varchar(65530), key(v(10)));
|
|
657 |
show create table t1;
|
|
658 |
Table Create Table
|
|
659 |
t1 CREATE TABLE `t1` (
|
|
660 |
`v` varchar(65530) DEFAULT NULL,
|
|
661 |
KEY `v` (`v`(10))
|
|
662 |
) ENGINE=MEMORY DEFAULT CHARSET=latin1
|
|
663 |
insert into t1 values(repeat('a',65530));
|
|
664 |
select length(v) from t1 where v=repeat('a',65530);
|
|
665 |
length(v)
|
|
666 |
65530
|
|
667 |
drop table t1;
|
|
668 |
set storage_engine=MyISAM;
|
|
669 |
create table t1 (a bigint unsigned auto_increment primary key, b int,
|
|
670 |
key (b, a)) engine=heap;
|
|
671 |
insert t1 (b) values (1),(1),(1),(1),(1),(1),(1),(1);
|
|
672 |
select * from t1;
|
|
673 |
a b
|
|
674 |
1 1
|
|
675 |
2 1
|
|
676 |
3 1
|
|
677 |
4 1
|
|
678 |
5 1
|
|
679 |
6 1
|
|
680 |
7 1
|
|
681 |
8 1
|
|
682 |
drop table t1;
|
|
683 |
create table t1 (a int not null, b int not null auto_increment,
|
|
684 |
primary key(a, b), key(b)) engine=heap;
|
|
685 |
insert t1 (a) values (1),(1),(1),(1),(1),(1),(1),(1);
|
|
686 |
select * from t1;
|
|
687 |
a b
|
|
688 |
1 1
|
|
689 |
1 2
|
|
690 |
1 3
|
|
691 |
1 4
|
|
692 |
1 5
|
|
693 |
1 6
|
|
694 |
1 7
|
|
695 |
1 8
|
|
696 |
drop table t1;
|
|
697 |
create table t1 (a int not null, b int not null auto_increment,
|
|
698 |
primary key(a, b)) engine=heap;
|
|
699 |
ERROR 42000: Incorrect table definition; there can be only one auto column and it must be defined as a key
|
|
700 |
create table t1 (c char(255), primary key(c(90)));
|
|
701 |
insert into t1 values ("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz");
|
|
702 |
insert into t1 values ("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz");
|
|
703 |
ERROR 23000: Duplicate entry 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijkl' for key 'PRIMARY'
|
|
704 |
drop table t1;
|
|
705 |
CREATE TABLE t1 (a int, key(a)) engine=heap;
|
|
706 |
insert into t1 values (0);
|
|
707 |
delete from t1;
|
|
708 |
select * from t1;
|
|
709 |
a
|
|
710 |
insert into t1 values (0), (1);
|
|
711 |
select * from t1 where a = 0;
|
|
712 |
a
|
|
713 |
0
|
|
714 |
drop table t1;
|
|
715 |
create table t1 (c char(10)) engine=memory;
|
|
716 |
create table t2 (c varchar(10)) engine=memory;
|
|
717 |
show table status like 't_';
|
|
718 |
Name Engine Version Row_format Rows Avg_row_length Data_length Max_data_length Index_length Data_free Auto_increment Create_time Update_time Check_time Collation Checksum Create_options Comment
|
|
719 |
t1 MEMORY 10 Fixed 0 11 0 # 0 0 NULL NULL NULL NULL latin1_swedish_ci NULL
|
|
720 |
t2 MEMORY 10 Fixed 0 12 0 # 0 0 NULL NULL NULL NULL latin1_swedish_ci NULL
|
|
721 |
drop table t1, t2;
|
|
722 |
CREATE TABLE t1(a VARCHAR(1), b VARCHAR(2), c VARCHAR(256),
|
|
723 |
KEY(a), KEY(b), KEY(c)) ENGINE=MEMORY;
|
|
724 |
INSERT INTO t1 VALUES('a','aa',REPEAT('a', 256)),('a','aa',REPEAT('a',256));
|
|
725 |
SELECT COUNT(*) FROM t1 WHERE a='a';
|
|
726 |
COUNT(*)
|
|
727 |
2
|
|
728 |
SELECT COUNT(*) FROM t1 WHERE b='aa';
|
|
729 |
COUNT(*)
|
|
730 |
2
|
|
731 |
SELECT COUNT(*) FROM t1 WHERE c=REPEAT('a',256);
|
|
732 |
COUNT(*)
|
|
733 |
2
|
|
734 |
DROP TABLE t1;
|
|
735 |
CREATE TABLE t1(c1 VARCHAR(100), c2 INT) ENGINE=MEMORY;
|
|
736 |
INSERT INTO t1 VALUES('', 0);
|
|
737 |
ALTER TABLE t1 MODIFY c1 VARCHAR(101);
|
|
738 |
SELECT c2 FROM t1;
|
|
739 |
c2
|
|
740 |
0
|
|
741 |
DROP TABLE t1;
|