EPCM-using CASE script in calculation

Summary:

How do I use CASE statements in formulas?

Content (required):

I use the following script, an error will happen. Could you tell me the correct syntax?

<script>

CASE

      WHEN (Member.DimensionA) < (Member.DimensionB) THEN (Member.DimensionC) := (Member.DimensionX)-(Member.DimensionZ]);

      ELSE (Member.DimensionC) :=0;

END

<Error>

 Invalid formula, the := operator is not found in the formula

Version (include the version you are using, if applicable):

23.07.62

Code Snippet (add any code snippets that support your topic, if applicable):