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drop table if exists t1;
create table t1 (t datetime);
insert into t1 values(101),(691231),(700101),(991231),(10000101),(99991231),(101000000),(691231000000),(700101000000),(991231235959),(10000101000000),(99991231235959),(20030102030460),(20030102036301),(20030102240401),(20030132030401),(20031302030460);
select * from t1;
t
2000-01-01 00:00:00
2069-12-31 00:00:00
1970-01-01 00:00:00
1999-12-31 00:00:00
1000-01-01 00:00:00
9999-12-31 00:00:00
2000-01-01 00:00:00
2069-12-31 00:00:00
1970-01-01 00:00:00
1999-12-31 23:59:59
1000-01-01 00:00:00
9999-12-31 23:59:59
0000-00-00 00:00:00
0000-00-00 00:00:00
0000-00-00 00:00:00
0000-00-00 00:00:00
0000-00-00 00:00:00
delete from t1 where t > 0;
optimize table t1;
Table Op Msg_type Msg_text
test.t1 optimize status OK
check table t1;
Table Op Msg_type Msg_text
test.t1 check status OK
delete from t1;
insert into t1 values("000101"),("691231"),("700101"),("991231"),("00000101"),("00010101"),("99991231"),("00101000000"),("691231000000"),("700101000000"),("991231235959"),("10000101000000"),("99991231235959"),("20030102030460"),("20030102036301"),("20030102240401"),("20030132030401"),("20031302030460");
select * from t1;
t
2000-01-01 00:00:00
2069-12-31 00:00:00
1970-01-01 00:00:00
1999-12-31 00:00:00
0000-01-01 00:00:00
0001-01-01 00:00:00
9999-12-31 00:00:00
2000-10-10 00:00:00
2069-12-31 00:00:00
1970-01-01 00:00:00
1999-12-31 23:59:59
1000-01-01 00:00:00
9999-12-31 23:59:59
0000-00-00 00:00:00
0000-00-00 00:00:00
0000-00-00 00:00:00
0000-00-00 00:00:00
0000-00-00 00:00:00
drop table t1;
CREATE TABLE t1 (a timestamp, b date, c time, d datetime);
insert into t1 (b,c,d) values(now(),curtime(),now());
select date_format(a,"%Y-%m-%d")=b,right(a,6)=c+0,a=d+0 from t1;
date_format(a,"%Y-%m-%d")=b right(a,6)=c+0 a=d+0
1 1 1
drop table t1;
CREATE TABLE t1 (a datetime not null);
insert into t1 values (0);
select * from t1 where a is null;
a
0000-00-00 00:00:00
drop table t1;
create table t1 (id int, dt datetime);
insert into t1 values (1,"2001-08-14 00:00:00"),(2,"2001-08-15 00:00:00"),(3,"2001-08-16 00:00:00"),(4,"2003-09-15 01:20:30");
select * from t1 where dt='2001-08-14 00:00:00' and dt = if(id=1,'2001-08-14 00:00:00','1999-08-15');
id dt
1 2001-08-14 00:00:00
create index dt on t1 (dt);
select * from t1 where dt > 20021020;
id dt
4 2003-09-15 01:20:30
select * from t1 ignore index (dt) where dt > 20021020;
id dt
4 2003-09-15 01:20:30
drop table t1;
CREATE TABLE `t1` (
`date` datetime NOT NULL default '0000-00-00 00:00:00',
`numfacture` int(6) unsigned NOT NULL default '0',
`expedition` datetime NOT NULL default '0000-00-00 00:00:00',
PRIMARY KEY (`numfacture`),
KEY `date` (`date`),
KEY `expedition` (`expedition`)
) TYPE=MyISAM;
INSERT INTO t1 (expedition) VALUES ('0001-00-00 00:00:00');
SELECT * FROM t1 WHERE expedition='0001-00-00 00:00:00';
date numfacture expedition
0000-00-00 00:00:00 0 0001-00-00 00:00:00
INSERT INTO t1 (numfacture,expedition) VALUES ('1212','0001-00-00 00:00:00');
SELECT * FROM t1 WHERE expedition='0001-00-00 00:00:00';
date numfacture expedition
0000-00-00 00:00:00 0 0001-00-00 00:00:00
0000-00-00 00:00:00 1212 0001-00-00 00:00:00
EXPLAIN SELECT * FROM t1 WHERE expedition='0001-00-00 00:00:00';
table type possible_keys key key_len ref rows Extra
t1 ref expedition expedition 8 const 1 Using where
drop table t1;
create table t1 (a datetime not null, b datetime not null);
insert into t1 values (now(), now());
insert into t1 values (now(), now());
select * from t1 where a is null or b is null;
a b
drop table t1;
create table t1 (dt datetime);
insert into t1 values ("12-00-00"), ("00-00-00 01:00:00");
insert into t1 values ("00-00-00"), ("00-00-00 00:00:00");
select * from t1;
dt
2012-00-00 00:00:00
2000-00-00 01:00:00
0000-00-00 00:00:00
0000-00-00 00:00:00
drop table t1;
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