The ALL keyword
Use the keyword ALL preceding a subquery to determine whether a comparison is true for every value returned. If the subquery returns no values, the search condition is true. (If it returns no values, the condition is true of all the zero values.)
The
following query lists the following information for all orders that
contain an item for which the total price is less than the total price
on every item in order number 1023.
Figure 1. Query
SELECT order_num, stock_num, manu_code, total_price
FROM items
WHERE total_price < ALL
(SELECT total_price FROM items
WHERE order_num = 1023);
Figure 2. Query
result
order_num stock_num manu_code total_price
1003 9 ANZ $20.00
1005 6 SMT $36.00
1006 6 SMT $36.00
1010 6 SMT $36.00
1013 5 ANZ $19.80
1013 6 SMT $36.00
1018 302 KAR $15.00