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sqloracle-databaseselect

Check if two "select"s are equivalent

Is there a way to check if two (non-trivial) select are equivalent?

Initially I was hoping for a formally equivalence between two selects, but the answers in proving-sql-query-equivalency stop me.

For my actual need I can just check if the (actual) results of two selects are the same.

Solution

  • If you want to compare the query results try the following:

    (select * from query1 MINUS select * from query2) 
UNION ALL
(select * from query2 MINUS select * from query1)

    This will result in all rows that are returned by only one of the queries.