Question

How can we use set operators to test a table for equality against a "known good" table?

Answer 1

Set operators like UNION, INTERSECT, and MINUS can be used to test a table for equality against a 'known good' table by comparing the two tables and checking for matches or differences.

Step-by-step explanation:

Set operators can be used to test a table for equality against a 'known good' table by comparing the two tables and checking for matches or differences. The set operators typically used for this purpose are UNION, INTERSECT, and MINUS (or EXCEPT in some databases).

For example, to test if two tables are equal, you can use the UNION operator to combine the rows from both tables and then compare the result with the 'known good' table. If the result of the UNION operation is equal to the 'known good' table, then the tested table is considered to be equal.

Here's an example:

SELECT * FROM tested_table UNION SELECT * FROM known_good_table;

If the result of this query is the same as the 'known good' table, then the two tables are equal.