1
drop table if exists t1;
2
select {fn length("hello")}, { date "1997-10-20" };
3
{fn length("hello")} 1997-10-20
5
create table t1 (a int not null auto_increment,b int not null,primary key (a,b));
6
insert into t1 SET A=NULL,B=1;
7
insert into t1 SET a=null,b=2;
8
select * from t1 where a is null and b=2;
11
select * from t1 where a is null;
13
explain select * from t1 where b is null;
14
id select_type table type possible_keys key key_len ref rows Extra
15
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
17
CREATE TABLE t1 (a INT AUTO_INCREMENT PRIMARY KEY);
18
INSERT INTO t1 VALUES (NULL);
19
SELECT sql_no_cache a, last_insert_id() FROM t1 WHERE a IS NULL;
22
SELECT sql_no_cache a, last_insert_id() FROM t1 WHERE a IS NULL;
24
SELECT sql_no_cache a, last_insert_id() FROM t1;