I'm trying to find a syntax that will take data from one table, compare it to another table, and return any anomalies that exist. Is this possible?
Most definitely possible.
select A.pk , A.col1, B.col1 , A.col2, B.col2 , A.col3, B.col3 from table_one as A inner join table_two as B on B.pk = A.pk where A.col1 <> B.col1 or A.col2 <> B.col2 or A.col3 <> B.col3 union all select A.pk , A.col1, null , A.col2, null , A.col3, null from table_one as A left outer join table_two as B on B.pk = A.pk where B.pk is null union all select B.pk , null, B.col1 , null, B.col2 , null, B.col3 from table_two as B left outer join table_one as A on A.pk = B.pk where A.pk is null
The inner join, with its WHERE conditions, returns rows which exist in both tables but which have at least one column different. Then the two outer joins, with their WHERE conditions, return rows which exist in one table but not the other. The results of these three subqueries are combined with UNION ALL to return all anomalies.
This was first published in March 2007