Describe the SQL set operations

The SQL set operations are :

1. Union Operation:
   • Think of it as stacking one query result on top of another.
   • If you have two queries, say Query A and Query B, the UNION operation combines the results of both.
   • It removes duplicate rows, so you only get distinct rows in the final result.
   • So, the result of a UNION operation contains all unique rows from both queries.

1. Intersect Operation:
   • Imagine you have two sets of data (results of two queries), and you want to find where they overlap.
   • The INTERSECT operation gives you the common rows that appear in both sets.
   • It only returns rows that are present in both queries’ results.
   • So, the result of an INTERSECT operation contains only the rows that are common in both queries.

1. Except Operation:
   • This operation is like subtracting one set of data from another.
   • If you have Query A and Query B, the EXCEPT operation gives you the rows that are in Query A but not in Query B.
   • It essentially removes the rows that are common between the two queries, leaving you with the rows unique to Query A.
   • So, the result of an EXCEPT operation contains only the rows that are exclusive to the first query.

In essence:

• UNION combines and removes duplicates.
• INTERSECT gives you common rows.
• EXCEPT gives you rows that are in the first query but not in the second query.