How Can SQL's CASE Statement Enable Dynamic Comparisons in the WHERE Clause?

Use the CASE statement in the WHERE clause of SQL for dynamic comparison

The CASE statement in SQL provides a conditional expression that evaluates a series of WHEN clauses and returns the corresponding value. This feature can be used in the WHERE clause to perform dynamic comparisons based on specific conditions.

To achieve the expected results, the CASE statement should be constructed as follows:

WHERE @locationID =
  CASE @locationType
      WHEN 'location' THEN account_location
      WHEN 'area' THEN xxx_location_area
      WHEN 'division' THEN xxx_location_division
  END

The above syntax ensures that the WHERE clause filters data based on the value of @locationType. If @locationType is 'location', the WHERE clause expression evaluates to @locationID = account_location. If @locationType is 'area', the WHERE clause evaluates to @locationID = xxx_location_area, and so on.

By using the CASE statement in this way, you avoid having to explicitly check each condition in the WHERE clause and ensure that the appropriate comparison is performed based on the provided @locationType value.

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