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e5a88caf08
assignments and comparison in query
A query that compares assignments of the same
user variable caused Valgrind warnings: access
to freed memory region.
In case of a DECIMAL argument the assignment
operator (:=) may return a pointer to a stored
value instead of its copy when evaluated.
The next assignment to the same variable may:
a) overwrite the stored value with a new one
and return the same pointer or even
b) reallocate stored value.
Thus, if we evaluate an assignment and keep
the result pointer and then evaluate another
assignment to the same variable, then the
kept result pointer of the first assignment
will point to unexpectedly changed data or
it may be a dead pointer.
That may cause wrong data or crash.
The user_var_entry::val_decimal method has
been modified to copy user variable data.
mysql-test/r/user_var.result:
Test case for bug #57187.
mysql-test/t/user_var.test:
Test case for bug #57187.
sql/item_func.cc:
Bug #57187: more user variable fun with multiple
assignments and comparison in query
The user_var_entry::val_decimal method has
been modified to copy user variable data.
459 lines
12 KiB
Text
459 lines
12 KiB
Text
drop table if exists t1,t2;
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set @a := foo;
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ERROR 42S22: Unknown column 'foo' in 'field list'
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set @a := connection_id() + 3;
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select @a - connection_id();
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@a - connection_id()
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3
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set @b := 1;
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select @b;
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@b
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1
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CREATE TABLE t1 ( i int not null, v int not null,index (i));
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insert into t1 values (1,1),(1,3),(2,1);
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create table t2 (i int not null, unique (i));
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insert into t2 select distinct i from t1;
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select * from t2;
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i
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1
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2
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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;
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i @vv1:=if(sv1.i,1,0) @vv2:=if(sv2.i,1,0) @vv3:=if(sv3.i,1,0) @vv1+@vv2+@vv3
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1 1 0 1 2
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2 1 0 0 1
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explain select * from t1 where i=@vv1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref i i 4 const 1
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select @vv1,i,v from t1 where i=@vv1;
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@vv1 i v
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1 1 1
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1 1 3
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explain select * from t1 where @vv1:=@vv1+1 and i=@vv1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where
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explain select @vv1:=i from t1 where i=@vv1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index NULL i 4 NULL 3 Using where; Using index
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explain select * from t1 where i=@vv1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref i i 4 const 1
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drop table t1,t2;
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set @a=0,@b=0;
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select @a:=10, @b:=1, @a > @b, @a < @b;
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@a:=10 @b:=1 @a > @b @a < @b
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10 1 1 0
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select @a:="10", @b:="1", @a > @b, @a < @b;
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@a:="10" @b:="1" @a > @b @a < @b
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10 1 1 0
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select @a:=10, @b:=2, @a > @b, @a < @b;
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@a:=10 @b:=2 @a > @b @a < @b
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10 2 0 1
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select @a:="10", @b:="2", @a > @b, @a < @b;
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@a:="10" @b:="2" @a > @b @a < @b
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10 2 1 0
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select @a:=1;
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@a:=1
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1
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select @a, @a:=1;
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@a @a:=1
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1 1
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create table t1 (id int, d double, c char(10));
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insert into t1 values (1,2.0, "test");
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select @c:=0;
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@c:=0
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0
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update t1 SET id=(@c:=@c+1);
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select @c;
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@c
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1
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select @c:=0;
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@c:=0
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0
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update t1 set id=(@c:=@c+1);
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select @c;
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@c
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1
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select @c:=0;
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@c:=0
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0
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select @c:=@c+1;
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@c:=@c+1
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1
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select @d,(@d:=id),@d from t1;
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@d (@d:=id) @d
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NULL 1 1
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select @e,(@e:=d),@e from t1;
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@e (@e:=d) @e
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NULL 2 2
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select @f,(@f:=c),@f from t1;
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@f (@f:=c) @f
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NULL test test
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set @g=1;
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select @g,(@g:=c),@g from t1;
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@g (@g:=c) @g
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1 test 0
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select @c, @d, @e, @f;
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@c @d @e @f
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1 1 2 test
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select @d:=id, @e:=id, @f:=id, @g:=@id from t1;
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@d:=id @e:=id @f:=id @g:=@id
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1 1 1 NULL
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select @c, @d, @e, @f, @g;
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@c @d @e @f @g
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1 1 1 1 NULL
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drop table t1;
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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;
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@a:=10 @b:=2 @a>@b @a:="10" @b:="2" @a>@b @a:=10 @b:=2 @a>@b @a:="10" @b:="2" @a>@b
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10 2 1 10 2 1 10 2 1 10 2 1
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create table t1 (i int not null);
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insert t1 values (1),(2),(2),(3),(3),(3);
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select @a:=0;
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@a:=0
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0
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select @a, @a:=@a+count(*), count(*), @a from t1 group by i;
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@a @a:=@a+count(*) count(*) @a
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0 1 1 0
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0 2 2 0
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0 3 3 0
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select @a:=0;
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@a:=0
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0
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select @a+0, @a:=@a+0+count(*), count(*), @a+0 from t1 group by i;
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@a+0 @a:=@a+0+count(*) count(*) @a+0
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0 1 1 0
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0 2 2 0
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0 3 3 0
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set @a=0;
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select @a,@a:="hello",@a,@a:=3,@a,@a:="hello again" from t1 group by i;
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@a @a:="hello" @a @a:=3 @a @a:="hello again"
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0 hello 0 3 0 hello again
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0 hello 0 3 0 hello again
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0 hello 0 3 0 hello again
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select @a,@a:="hello",@a,@a:=3,@a,@a:="hello again" from t1 group by i;
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@a @a:="hello" @a @a:=3 @a @a:="hello again"
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hello again hello hello again 3 hello again hello again
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hello again hello hello again 3 hello again hello again
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hello again hello hello again 3 hello again hello again
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drop table t1;
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set @a=_latin2'test';
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select charset(@a),collation(@a),coercibility(@a);
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charset(@a) collation(@a) coercibility(@a)
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latin2 latin2_general_ci 2
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select @a=_latin2'TEST';
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@a=_latin2'TEST'
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1
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select @a=_latin2'TEST' collate latin2_bin;
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@a=_latin2'TEST' collate latin2_bin
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0
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set @a=_latin2'test' collate latin2_general_ci;
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select charset(@a),collation(@a),coercibility(@a);
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charset(@a) collation(@a) coercibility(@a)
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latin2 latin2_general_ci 2
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select @a=_latin2'TEST';
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@a=_latin2'TEST'
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1
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select @a=_latin2'TEST' collate latin2_bin;
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@a=_latin2'TEST' collate latin2_bin
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0
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select charset(@a:=_latin2'test');
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charset(@a:=_latin2'test')
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latin2
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select collation(@a:=_latin2'test');
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collation(@a:=_latin2'test')
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latin2_general_ci
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select coercibility(@a:=_latin2'test');
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coercibility(@a:=_latin2'test')
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2
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select collation(@a:=_latin2'test' collate latin2_bin);
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collation(@a:=_latin2'test' collate latin2_bin)
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latin2_bin
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select coercibility(@a:=_latin2'test' collate latin2_bin);
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coercibility(@a:=_latin2'test' collate latin2_bin)
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2
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select (@a:=_latin2'test' collate latin2_bin) = _latin2'TEST';
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(@a:=_latin2'test' collate latin2_bin) = _latin2'TEST'
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0
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select charset(@a),collation(@a),coercibility(@a);
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charset(@a) collation(@a) coercibility(@a)
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latin2 latin2_bin 2
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select (@a:=_latin2'test' collate latin2_bin) = _latin2'TEST' collate latin2_general_ci;
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(@a:=_latin2'test' collate latin2_bin) = _latin2'TEST' collate latin2_general_ci
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1
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set @var= NULL ;
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select FIELD( @var,'1it','Hit') as my_column;
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my_column
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0
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select @v, coercibility(@v);
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@v coercibility(@v)
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NULL 2
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set @v1=null, @v2=1, @v3=1.1, @v4=now();
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select coercibility(@v1),coercibility(@v2),coercibility(@v3),coercibility(@v4);
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coercibility(@v1) coercibility(@v2) coercibility(@v3) coercibility(@v4)
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2 2 2 2
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set session @honk=99;
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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
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set one_shot @honk=99;
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ERROR HY000: The 'SET ONE_SHOT' syntax is reserved for purposes internal to the MySQL server
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select @@local.max_allowed_packet;
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@@local.max_allowed_packet
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#
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select @@session.max_allowed_packet;
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@@session.max_allowed_packet
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#
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select @@global.max_allowed_packet;
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@@global.max_allowed_packet
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#
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select @@max_allowed_packet;
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@@max_allowed_packet
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#
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select @@Max_Allowed_Packet;
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@@Max_Allowed_Packet
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#
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select @@version;
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@@version
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#
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select @@global.version;
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@@global.version
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#
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End of 4.1 tests
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set @first_var= NULL;
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create table t1 select @first_var;
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`@first_var` longblob
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) ENGINE=MyISAM DEFAULT CHARSET=latin1
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drop table t1;
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set @first_var= cast(NULL as signed integer);
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create table t1 select @first_var;
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`@first_var` bigint(20) DEFAULT NULL
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) ENGINE=MyISAM DEFAULT CHARSET=latin1
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drop table t1;
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set @first_var= NULL;
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create table t1 select @first_var;
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`@first_var` bigint(20) DEFAULT NULL
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) ENGINE=MyISAM DEFAULT CHARSET=latin1
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drop table t1;
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set @first_var= concat(NULL);
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create table t1 select @first_var;
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`@first_var` longblob
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) ENGINE=MyISAM DEFAULT CHARSET=latin1
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drop table t1;
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set @first_var=1;
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set @first_var= cast(NULL as CHAR);
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create table t1 select @first_var;
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`@first_var` longtext
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) ENGINE=MyISAM DEFAULT CHARSET=latin1
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drop table t1;
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set @a=18446744071710965857;
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select @a;
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@a
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18446744071710965857
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CREATE TABLE `bigfailure` (
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`afield` BIGINT UNSIGNED NOT NULL
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);
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INSERT INTO `bigfailure` VALUES (18446744071710965857);
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SELECT * FROM bigfailure;
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afield
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18446744071710965857
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select * from (SELECT afield FROM bigfailure) as b;
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afield
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18446744071710965857
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select * from bigfailure where afield = (SELECT afield FROM bigfailure);
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afield
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18446744071710965857
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select * from bigfailure where afield = 18446744071710965857;
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afield
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18446744071710965857
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select * from bigfailure where afield = 18446744071710965856+1;
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afield
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18446744071710965857
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SET @a := (SELECT afield FROM bigfailure);
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SELECT @a;
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@a
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18446744071710965857
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SET @a := (select afield from (SELECT afield FROM bigfailure) as b);
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SELECT @a;
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@a
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18446744071710965857
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SET @a := (select * from bigfailure where afield = (SELECT afield FROM bigfailure));
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SELECT @a;
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@a
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18446744071710965857
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drop table bigfailure;
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create table t1(f1 int, f2 int);
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insert into t1 values (1,2),(2,3),(3,1);
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select @var:=f2 from t1 group by f1 order by f2 desc limit 1;
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@var:=f2
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3
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select @var;
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@var
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3
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create table t2 as select @var:=f2 from t1 group by f1 order by f2 desc limit 1;
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select * from t2;
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@var:=f2
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3
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select @var;
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@var
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3
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drop table t1,t2;
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insert into city 'blah';
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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
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SHOW COUNT(*) WARNINGS;
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@@session.warning_count
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1
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SHOW COUNT(*) ERRORS;
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@@session.error_count
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1
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create table t1(f1 int, f2 varchar(2), f3 float, f4 decimal(2,1));
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insert into t1 values
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(1, "a", 1.5, 1.6), (1, "a", 1.5, 1.6), (2, "b", 2.5, 2.6),
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(3, "c", 3.5, 3.6), (4, "d", 4.5, 4.6), (1, "a", 1.5, 1.6),
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(3, "c", 3.5, 3.6), (1, "a", 1.5, 1.6);
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select @a:=f1, count(f1) from t1 group by 1 desc;
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@a:=f1 count(f1)
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4 1
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3 2
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2 1
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1 4
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select @a:=f1, count(f1) from t1 group by 1 asc;
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@a:=f1 count(f1)
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1 4
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2 1
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3 2
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4 1
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select @a:=f2, count(f2) from t1 group by 1 desc;
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@a:=f2 count(f2)
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d 1
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c 2
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b 1
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a 4
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select @a:=f3, count(f3) from t1 group by 1 desc;
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@a:=f3 count(f3)
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4.5 1
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3.5 2
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2.5 1
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1.5 4
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select @a:=f4, count(f4) from t1 group by 1 desc;
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@a:=f4 count(f4)
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4.6 1
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3.6 2
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2.6 1
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1.6 4
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drop table t1;
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create table t1 (f1 int);
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insert into t1 values (2), (1);
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select @i := f1 as j from t1 order by 1;
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j
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1
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2
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drop table t1;
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create table t1(a int);
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insert into t1 values(5),(4),(4),(3),(2),(2),(2),(1);
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set @rownum := 0;
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set @rank := 0;
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set @prev_score := NULL;
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select @rownum := @rownum + 1 as row,
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@rank := IF(@prev_score!=a, @rownum, @rank) as rank,
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@prev_score := a as score
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from t1 order by score desc;
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drop table t1;
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create table t1(b bigint);
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insert into t1 (b) values (10), (30), (10);
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set @var := 0;
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select if(b=@var, 999, b) , @var := b from t1 order by b;
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if(b=@var, 999, b) @var := b
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10 10
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999 10
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30 30
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drop table t1;
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create temporary table t1 (id int);
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insert into t1 values (2), (3), (3), (4);
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set @lastid=-1;
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select @lastid != id, @lastid, @lastid := id from t1;
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@lastid != id @lastid @lastid := id
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1 -1 2
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1 2 3
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0 3 3
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1 3 4
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drop table t1;
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create temporary table t1 (id bigint);
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insert into t1 values (2), (3), (3), (4);
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set @lastid=-1;
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select @lastid != id, @lastid, @lastid := id from t1;
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@lastid != id @lastid @lastid := id
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1 -1 2
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1 2 3
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0 3 3
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1 3 4
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drop table t1;
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CREATE TABLE t1(a INT, b INT);
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INSERT INTO t1 VALUES (0, 0), (2, 1), (2, 3), (1, 1), (30, 20);
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SELECT a, b INTO @a, @b FROM t1 WHERE a=2 AND b=3 GROUP BY a, b;
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SELECT @a, @b;
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@a @b
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2 3
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SELECT a, b FROM t1 WHERE a=2 AND b=3 GROUP BY a, b;
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a b
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2 3
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DROP TABLE t1;
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CREATE TABLE t1 (f1 int(11) default NULL, f2 int(11) default NULL);
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CREATE TABLE t2 (f1 int(11) default NULL, f2 int(11) default NULL, foo int(11));
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CREATE TABLE t3 (f1 int(11) default NULL, f2 int(11) default NULL);
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INSERT INTO t1 VALUES(10, 10);
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INSERT INTO t1 VALUES(10, 10);
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INSERT INTO t2 VALUES(10, 10, 10);
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INSERT INTO t2 VALUES(10, 10, 10);
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INSERT INTO t3 VALUES(10, 10);
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INSERT INTO t3 VALUES(10, 10);
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SELECT MIN(t2.f1),
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@bar:= (SELECT MIN(t3.f2) FROM t3 WHERE t3.f2 > foo)
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FROM t1,t2 WHERE t1.f1 = t2.f1 ORDER BY t2.f1;
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MIN(t2.f1) @bar:= (SELECT MIN(t3.f2) FROM t3 WHERE t3.f2 > foo)
|
|
10 NULL
|
|
DROP TABLE t1, t2, t3;
|
|
End of 5.0 tests
|
|
CREATE TABLE t1 (i INT);
|
|
CREATE TRIGGER t_after_insert AFTER INSERT ON t1 FOR EACH ROW SET @bug42188 = 10;
|
|
INSERT INTO t1 VALUES (1);
|
|
INSERT INTO t1 VALUES (1);
|
|
DROP TABLE t1;
|
|
CREATE TABLE t1(a INT);
|
|
INSERT INTO t1 VALUES (0),(0);
|
|
# BUG#55615 : should not crash
|
|
SELECT (@a:=(SELECT @a:=1 FROM t1 LIMIT 1)) AND COUNT(1) FROM t1 GROUP BY @a;
|
|
(@a:=(SELECT @a:=1 FROM t1 LIMIT 1)) AND COUNT(1)
|
|
1
|
|
1
|
|
# BUG#55564 : should not crash
|
|
SELECT IF(
|
|
@v:=LEAST((SELECT 1 FROM t1 t2 LEFT JOIN t1 ON (@v) GROUP BY t1.a), a),
|
|
count(*), 1)
|
|
FROM t1 GROUP BY a LIMIT 1;
|
|
IF(
|
|
@v:=LEAST((SELECT 1 FROM t1 t2 LEFT JOIN t1 ON (@v) GROUP BY t1.a), a),
|
|
count(*), 1)
|
|
1
|
|
DROP TABLE t1;
|
|
select @v:=@v:=sum(1) from dual;
|
|
@v:=@v:=sum(1)
|
|
1
|
|
CREATE TABLE t1(a DECIMAL(31,21));
|
|
INSERT INTO t1 VALUES (0);
|
|
SELECT (@v:=a) <> (@v:=1) FROM t1;
|
|
(@v:=a) <> (@v:=1)
|
|
1
|
|
DROP TABLE t1;
|
|
End of 5.1 tests
|