TRY: select Name from syscolumns a left join syscolumns b on a.name=b.name and a.colid=1 and b.colid=1 and a.id<>b.id left join syscolumns c on a.name=c.name and a.colid=2 and c.colid=2 and a.id<>c.id and b.id<>c.id
select a,b from tabel1,table2
select 字段1,字段2 from 库名1..表名1 ,库名2..表名2
select A,b from t1 union all select a,b from t2
select a,b from t1 union select a,b from database2..t2
select Name from syscolumns a left join syscolumns b on a.name=b.name and a.colid=1 and b.colid=1 and a.id<>b.id
left join syscolumns c on a.name=c.name and a.colid=2 and c.colid=2 and a.id<>c.id and b.id<>c.id
union all
select a,b from t2
union
select a,b from database2..t2