user_var.result

来自「视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.」· RESULT 代码 · 共 356 行

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
#
End of 4.1 tests
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
create table t2 as select @var:=f2 from t1 group by f1 order by f2 desc limit 1;
select * from t2;
@var:=f2
3
select @var;
@var
3
drop table t1,t2;
insert into city 'blah';
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 ''blah'' at line 1
SHOW COUNT(*) WARNINGS;
@@session.warning_count
1
SHOW COUNT(*) ERRORS;
@@session.error_count
1
create table t1(f1 int, f2 varchar(2), f3 float, f4 decimal(2,1));
insert into t1 values 
(1, "a", 1.5, 1.6), (1, "a", 1.5, 1.6), (2, "b", 2.5, 2.6),
(3, "c", 3.5, 3.6), (4, "d", 4.5, 4.6), (1, "a", 1.5, 1.6),
(3, "c", 3.5, 3.6), (1, "a", 1.5, 1.6);
select @a:=f1, count(f1) from t1 group by 1 desc;
@a:=f1	count(f1)
4	1
3	2
2	1
1	4
select @a:=f1, count(f1) from t1 group by 1 asc;
@a:=f1	count(f1)
1	4
2	1
3	2
4	1
select @a:=f2, count(f2) from t1 group by 1 desc;
@a:=f2	count(f2)
d	1
c	2
b	1
a	4
select @a:=f3, count(f3) from t1 group by 1 desc;
@a:=f3	count(f3)
4.5	1
3.5	2
2.5	1
1.5	4
select @a:=f4, count(f4) from t1 group by 1 desc;
@a:=f4	count(f4)
4.6	1
3.6	2
2.6	1
1.6	4
drop table t1;