case_expression

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4D v16

case_expression



	case_expression

Beschreibung

A case_expression is used to apply one or more conditions when selecting an expression.

They can be used as follows, for example:

CASE
WHEN search_condition THEN arithmetic_expression
...
WHEN search_condition THEN arithmetic_expression
[ELSE arithmetic_expression]
END

Or:

CASE arithmetic_expression
WHEN arithmetic_expression THEN arithmetic_expression
...
WHEN arithmetic_expression THEN arithmetic_expression
[ELSE arithmetic_expression]
END

Beispiel

This example selects records from the ROOM_NUMBER column according to the value of the ROOM_FLOOR column:

SELECT ROOM_NUMBER
CASE ROOM_FLOOR
WHEN 'Ground floor' THEN 0
WHEN 'First floor' THEN 1
WHEN 'Second floor' THEN 2
END AS FLOORS, SLEEPING_ROOM
FROM T_ROOMS
ORDER BY FLOORS, SLEEPING_ROOM

Siehe auch

arithmetic_expression
search_condition