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drop table if exists t1,t2;
set @a := foo;
ERROR 42S22: Unknown column 'foo' in 'field list'
set @a := connection_id() + 3;
select @a - connection_id();
@a - connection_id()
3
set @b := 1;
select @b;
@b
1
CREATE TABLE t1 ( i int not null, v int not null,index (i));
insert into t1 values (1,1),(1,3),(2,1);
create table t2 (i int not null, unique (i));
insert into t2 select distinct i from t1;
select * from t2;
i
1
2
select distinct t2.i,@vv1:=if(sv1.i,1,0),@vv2:=if(sv2.i,1,0),@vv3:=if(sv3.i,1,0), @vv1+@vv2+@vv3 from t2 left join t1 as sv1 on sv1.i=t2.i and sv1.v=1 left join t1 as sv2 on sv2.i=t2.i and sv2.v=2 left join t1 as sv3 on sv3.i=t2.i and sv3.v=3;
i @vv1:=if(sv1.i,1,0) @vv2:=if(sv2.i,1,0) @vv3:=if(sv3.i,1,0) @vv1+@vv2+@vv3
1 1 0 1 2
2 1 0 0 1
explain select * from t1 where i=@vv1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref i i 4 const 1
select @vv1,i,v from t1 where i=@vv1;
@vv1 i v
1 1 1
1 1 3
explain select * from t1 where @vv1:=@vv1+1 and i=@vv1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where
explain select @vv1:=i from t1 where i=@vv1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL i 4 NULL 3 Using where; Using index
explain select * from t1 where i=@vv1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref i i 4 const 1
drop table t1,t2;
set @a=0,@b=0;
select @a:=10, @b:=1, @a > @b, @a < @b;
@a:=10 @b:=1 @a > @b @a < @b
10 1 1 0
select @a:="10", @b:="1", @a > @b, @a < @b;
@a:="10" @b:="1" @a > @b @a < @b
10 1 1 0
select @a:=10, @b:=2, @a > @b, @a < @b;
@a:=10 @b:=2 @a > @b @a < @b
10 2 0 1
select @a:="10", @b:="2", @a > @b, @a < @b;
@a:="10" @b:="2" @a > @b @a < @b
10 2 1 0
select @a:=1;
@a:=1
1
select @a, @a:=1;
@a @a:=1
1 1
create table t1 (id int, d double, c char(10));
insert into t1 values (1,2.0, "test");
select @c:=0;
@c:=0
0
update t1 SET id=(@c:=@c+1);
select @c;
@c
1
select @c:=0;
@c:=0
0
update t1 set id=(@c:=@c+1);
select @c;
@c
1
select @c:=0;
@c:=0
0
select @c:=@c+1;
@c:=@c+1
1
select @d,(@d:=id),@d from t1;
@d (@d:=id) @d
NULL 1 1
select @e,(@e:=d),@e from t1;
@e (@e:=d) @e
NULL 2 2
select @f,(@f:=c),@f from t1;
@f (@f:=c) @f
NULL test test
set @g=1;
select @g,(@g:=c),@g from t1;
@g (@g:=c) @g
1 test test
select @c, @d, @e, @f;
@c @d @e @f
1 1 2 test
select @d:=id, @e:=id, @f:=id, @g:=@id from t1;
@d:=id @e:=id @f:=id @g:=@id
1 1 1 NULL
select @c, @d, @e, @f, @g;
@c @d @e @f @g
1 1 1 1 NULL
drop table t1;
select @a:=10, @b:=2, @a>@b, @a:="10", @b:="2", @a>@b, @a:=10, @b:=2, @a>@b, @a:="10", @b:="2", @a>@b;
@a:=10 @b:=2 @a>@b @a:="10" @b:="2" @a>@b @a:=10 @b:=2 @a>@b @a:="10" @b:="2" @a>@b
10 2 1 10 2 1 10 2 1 10 2 1
create table t1 (i int not null);
insert t1 values (1),(2),(2),(3),(3),(3);
select @a:=0;
@a:=0
0
select @a, @a:=@a+count(*), count(*), @a from t1 group by i;
@a @a:=@a+count(*) count(*) @a
0 1 1 0
0 2 2 0
0 3 3 0
select @a:=0;
@a:=0
0
select @a+0, @a:=@a+0+count(*), count(*), @a+0 from t1 group by i;
@a+0 @a:=@a+0+count(*) count(*) @a+0
0 1 1 0
1 3 2 0
3 6 3 0
set @a=0;
select @a,@a:="hello",@a,@a:=3,@a,@a:="hello again" from t1 group by i;
@a @a:="hello" @a @a:=3 @a @a:="hello again"
0 hello 0 3 0 hello again
0 hello 0 3 0 hello again
0 hello 0 3 0 hello again
select @a,@a:="hello",@a,@a:=3,@a,@a:="hello again" from t1 group by i;
@a @a:="hello" @a @a:=3 @a @a:="hello again"
hello again hello hello again 3 hello again hello again
hello again hello hello again 3 hello again hello again
hello again hello hello again 3 hello again hello again
drop table t1;
set @a=_latin2'test';
select charset(@a),collation(@a),coercibility(@a);
charset(@a) collation(@a) coercibility(@a)
latin2 latin2_general_ci 2
select @a=_latin2'TEST';
@a=_latin2'TEST'
1
select @a=_latin2'TEST' collate latin2_bin;
@a=_latin2'TEST' collate latin2_bin
0
set @a=_latin2'test' collate latin2_general_ci;
select charset(@a),collation(@a),coercibility(@a);
charset(@a) collation(@a) coercibility(@a)
latin2 latin2_general_ci 2
select @a=_latin2'TEST';
@a=_latin2'TEST'
1
select @a=_latin2'TEST' collate latin2_bin;
@a=_latin2'TEST' collate latin2_bin
0
select charset(@a:=_latin2'test');
charset(@a:=_latin2'test')
latin2
select collation(@a:=_latin2'test');
collation(@a:=_latin2'test')
latin2_general_ci
select coercibility(@a:=_latin2'test');
coercibility(@a:=_latin2'test')
2
select collation(@a:=_latin2'test' collate latin2_bin);
collation(@a:=_latin2'test' collate latin2_bin)
latin2_bin
select coercibility(@a:=_latin2'test' collate latin2_bin);
coercibility(@a:=_latin2'test' collate latin2_bin)
2
select (@a:=_latin2'test' collate latin2_bin) = _latin2'TEST';
(@a:=_latin2'test' collate latin2_bin) = _latin2'TEST'
0
select charset(@a),collation(@a),coercibility(@a);
charset(@a) collation(@a) coercibility(@a)
latin2 latin2_bin 2
select (@a:=_latin2'test' collate latin2_bin) = _latin2'TEST' collate latin2_general_ci;
(@a:=_latin2'test' collate latin2_bin) = _latin2'TEST' collate latin2_general_ci
1
set @var= NULL ;
select FIELD( @var,'1it','Hit') as my_column;
my_column
0
select @v, coercibility(@v);
@v coercibility(@v)
NULL 2
set @v1=null, @v2=1, @v3=1.1, @v4=now();
select coercibility(@v1),coercibility(@v2),coercibility(@v3),coercibility(@v4);
coercibility(@v1) coercibility(@v2) coercibility(@v3) coercibility(@v4)
2 2 2 2
set session @honk=99;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '@honk=99' at line 1
set one_shot @honk=99;
ERROR HY000: The 'SET ONE_SHOT' syntax is reserved for purposes internal to the MySQL server
select @@local.max_allowed_packet;
@@local.max_allowed_packet
#
select @@session.max_allowed_packet;
@@session.max_allowed_packet
#
select @@global.max_allowed_packet;
@@global.max_allowed_packet
#
select @@max_allowed_packet;
@@max_allowed_packet
#
select @@Max_Allowed_Packet;
@@Max_Allowed_Packet
#
select @@version;
@@version
#
select @@global.version;
@@global.version
#
set @first_var= NULL;
create table t1 select @first_var;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`@first_var` longblob
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
set @first_var= cast(NULL as signed integer);
create table t1 select @first_var;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`@first_var` bigint(20) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
set @first_var= NULL;
create table t1 select @first_var;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`@first_var` bigint(20) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
set @first_var= concat(NULL);
create table t1 select @first_var;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`@first_var` longblob
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
set @first_var=1;
set @first_var= cast(NULL as CHAR);
create table t1 select @first_var;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`@first_var` longtext
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
set @a=18446744071710965857;
select @a;
@a
18446744071710965857
CREATE TABLE `bigfailure` (
`afield` BIGINT UNSIGNED NOT NULL
);
INSERT INTO `bigfailure` VALUES (18446744071710965857);
SELECT * FROM bigfailure;
afield
18446744071710965857
select * from (SELECT afield FROM bigfailure) as b;
afield
18446744071710965857
select * from bigfailure where afield = (SELECT afield FROM bigfailure);
afield
18446744071710965857
select * from bigfailure where afield = 18446744071710965857;
afield
18446744071710965857
select * from bigfailure where afield = 18446744071710965856+1;
afield
18446744071710965857
SET @a := (SELECT afield FROM bigfailure);
SELECT @a;
@a
18446744071710965857
SET @a := (select afield from (SELECT afield FROM bigfailure) as b);
SELECT @a;
@a
18446744071710965857
SET @a := (select * from bigfailure where afield = (SELECT afield FROM bigfailure));
SELECT @a;
@a
18446744071710965857
drop table bigfailure;
create table t1(f1 int, f2 int);
insert into t1 values (1,2),(2,3),(3,1);
select @var:=f2 from t1 group by f1 order by f2 desc limit 1;
@var:=f2
3
select @var;
@var
3
drop table t1;
End of 4.1 tests