SQL TutorialLesson 41Free preview

SQL Case

This lesson is part of SQL · All levels

Summary

CASE gives branching logic within a query, similar to if-else in a programming language. The result could be a new column that displays the label under the conditions it meets. There is a simple form of case when and a system form with case expression when values.

Key points

Case when... then... else... and then yield value based on the condition.
The evaluation of the branch is done from top to bottom; the first appropriate branch is used.
ELSE is optional; without ELSE the result is when there is no suitable branch.
It can be used in SELECT, WHERE, ORDER BY, or GROUP BY.
CASE form expression: CASE status when 1 THEN 'active'... END.

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