16.20 - Example: Using a CASE Expression - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL Functions, Expressions, and Predicates

Product
Advanced SQL Engine
Teradata Database
Release Number
16.20
Release Date
March 2019
Content Type
Programming Reference
Publication ID
B035-1145-162K
Language
English (United States)

CASE expressions can be used in place of any value-expressions.

Note that the following example does not specify an ELSE clause. ELSE clauses are always optional in a CASE expression. If an ELSE clause is not specified and none of the WHEN conditions are TRUE, then a null is returned.

   SELECT * 
   FROM t 
   WHERE x = CASE 
              WHEN y=2 
              THEN 1
              WHEN (z=3 AND y=5) 
              THEN 2 
             END;