SQL Query: A Simple Use of SQL CASE Expression

What is CASE Expression 

CASE is the special scalar expression in SQL language. CASE expression is widely used to facilitate determining / setting a new value from user input values. CASE expression can be used for various purposes which depends on the business logic.

CASE expression is mostly used in SQL stored procedure or as a formula for a particular column, which optimizes the SQL statements.

Syntax of CASE Expression 

SQL CASE expression is used as a type of IF-THEN-ELSE statement. It is similar to switch statement in recent programming languages such as C# and Java. The syntax of the CASE statement is simple as follows:

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1.    CASE column_name  
2.      WHEN condition1 THEN result1  
3.      WHEN condition2 THEN result2  
4.      ...  
5.      ELSE result  
6.    END