sel_union.sql

The following example uses the UNION clause to query on data in two tables. The compound query performs a union on the stock_num and manu_code columns in the stock and items tables. The statement selects items that have a unit price of less than $25.00 or that have been ordered in quantities greater than three, and it lists their stock_num and manu_code.

SELECT DISTINCT stock_num, manu_code
   FROM stock
   WHERE unit_price < 25.00

UNION

SELECT stock_num, manu_code
   FROM items
   WHERE quantity > 3;