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