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drop table if exists t1,t2;
select 0<=>0,0.0<=>0.0,"A"<=>"A",NULL<=>NULL;
0<=>0 0.0<=>0.0 "A"<=>"A" NULL<=>NULL
1 1 1 1
select 1<=>0,0<=>NULL,NULL<=>0;
1<=>0 0<=>NULL NULL<=>0
0 0 0
select 1.0<=>0.0,0.0<=>NULL,NULL<=>0.0;
1.0<=>0.0 0.0<=>NULL NULL<=>0.0
0 0 0
select "A"<=>"B","A"<=>NULL,NULL<=>"A";
"A"<=>"B" "A"<=>NULL NULL<=>"A"
0 0 0
create table t1 (id int, value int);
create table t2 (id int, value int);
insert into t1 values (1,null);
insert into t2 values (1,null);
select t1.*, t2.*, t1.value<=>t2.value from t1, t2 where t1.id=t2.id and t1.id=1;
id value id value t1.value<=>t2.value
1 NULL 1 NULL 1
select * from t1 where id <=>id;
id value
1 NULL
select * from t1 where value <=> value;
id value
1 NULL
select * from t1 where id <=> value or value<=>id;
id value
drop table t1,t2;
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