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select database();
database()
test
select charset(database());
charset(database())
utf8
select database() = "test";
database() = "test"
1
select database() = _utf8"test";
database() = _utf8"test"
1
select database() = _latin1"test";
database() = _latin1"test"
1
select user() like "%@%";
user() like "%@%"
1
select user() like _utf8"%@%";
user() like _utf8"%@%"
1
select user() like _latin1"%@%";
user() like _latin1"%@%"
1
select charset(user());
charset(user())
utf8
select version()>="03.23.29";
version()>="03.23.29"
1
select version()>=_utf8"03.23.29";
version()>=_utf8"03.23.29"
1
select version()>=_latin1"03.23.29";
version()>=_latin1"03.23.29"
1
select charset(version());
charset(version())
utf8
explain extended select database(), user();
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select database() AS `database()`,user() AS `user()`
create table t1 (version char(60)) select database(), user(), version() as 'version';
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`database()` varchar(34) CHARACTER SET utf8 DEFAULT NULL,
`user()` varchar(384) CHARACTER SET utf8 DEFAULT NULL,
`version` char(60) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
select charset(charset(_utf8'a')), charset(collation(_utf8'a'));
charset(charset(_utf8'a')) charset(collation(_utf8'a'))
utf8 utf8
select collation(charset(_utf8'a')), collation(collation(_utf8'a'));
collation(charset(_utf8'a')) collation(collation(_utf8'a'))
utf8_general_ci utf8_general_ci
create table t1 select charset(_utf8'a'), collation(_utf8'a');
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`charset(_utf8'a')` varchar(64) CHARACTER SET utf8 DEFAULT NULL,
`collation(_utf8'a')` varchar(64) CHARACTER SET utf8 DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
select TRUE,FALSE,NULL;
TRUE FALSE NULL
1 0 NULL
create table t1 (c1 char(5)) character set=latin1;
insert into t1 values('row 1');
insert into t1 values('row 2');
insert into t1 values('row 3');
select concat(user(), '--', c1) from t1;
concat(user(), '--', c1)
root@localhost--row 1
root@localhost--row 2
root@localhost--row 3
select concat(database(), '--', c1) from t1;
concat(database(), '--', c1)
test--row 1
test--row 2
test--row 3
drop table t1;
create table t1 (a char(10)) character set latin1;
select * from t1 where a=version();
a
select * from t1 where a=database();
a
select * from t1 where a=user();
a
insert into t1 values ('a');
select left(concat(a,version()),1) from t1;
left(concat(a,version()),1)
a
drop table t1;
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