creat view [视图名] as select 1 as sx,a,b,c from t1 union all select 2 as sx,a,b,c from t2 union all select 3 as sx,a,b,c from t3
creat view [视图名] as select 1 as sx,a,b,c from t1 union all select 2 as sx,a,b,c from t2 union all select 3 as sx,a,b,c from t3