CASE Expression

An expression that chooses a result by evaluating conditions in order.

What does CASE Expression do in a relational database?

CASE Expression — An expression that chooses a result by evaluating conditions in order.

SELECT order_id,
       CASE
           WHEN total_amount >= 100 THEN 'large'
           ELSE 'standard'
       END AS size
FROM purchase_order;

Level: Apprentice · More Database terms at this level

Updated September 27, 2026