CASE (Searched)

CASE statements evaluate one or more conditions and return a result when the first condition is met, or a default result if none of the conditions are met.

Note: there are two forms of the CASE statement: searched CASE and simple CASE. Searched CASE statements allow you to use more sophisticated logic, while simple CASE statements are simpler to construct.

See also: IF.

In this article:

• Sample usage
• Syntax
• How searched CASE works
• Examples
• Related resources

Sample usage

A common use for CASE is to create new categories or groupings of data. For example, to group selected country values into a Sales Region dimension, you might create a CASE statement like this:

CASE 
    WHEN Country IN ("USA","Canada","Mexico") THEN "North America" 
    WHEN Country IN ("England","France") THEN "Europe" 
    ELSE "Other" 
END

Syntax

CASE
    WHEN condition THEN result
    [WHEN condition THEN result]
    [...]
    [ELSE else_result]
END

Parameters

• condition - A logical field or expression. WHEN clauses evaluate condition and return true if the specified condition is met, or false if the condition isn't met.

• result - A field or expression of any type. Each WHEN clause must have a matching THEN clause, which specifies the results if that WHEN condition is true. If there are multiple WHEN clauses, the CASE statement returns the result for the first true condition.

• else_result (optional) - A field or expression of any type. The ELSE else_result clause specifies a default result for the CASE statement. This clause is returned if none of the WHEN clauses are true. If a CASE statement has no ELSE clause, and none of the WHEN clauses are true, the CASE statement returns NULL.

A CASE statement can have only one ELSE clause.

Note: All of the THEN clauses in a CASE statement must return the same data type. For example, if the first THEN clause returns the Text data type, additional THEN clauses must also return the Text data type.

How searched CASE works

A searched CASE statement begins with the CASE keyword and ends with the END keyword. In between, you'll have a number of sections or clauses:

• WHEN: A condition that you want to evaluate. You can have multiple WHEN clauses in a single CASE statement.
• THEN: The result to return if the WHEN clause's condition is true. You must have one THEN clause for each WHEN clause in your CASE statement.
• ELSE: Optional. If none of the WHEN clause conditions are true, CASE returns the value in the ELSE clause, or NULL if no ELSE clause is specified.

CASE evaluates each successive WHEN clause and returns the first result where the condition is true. Any remaining WHEN clauses and the ELSE result are not evaluated. If all WHEN conditions are false or NULL, CASE returns the ELSE result, or if no ELSE clause is present, returns NULL.

Examples

Check for inequality

CASE WHEN Medium != "cpc" THEN "free" ELSE "paid" END

For simple scenarios, consider using the IF function.

Classify numeric dimension values into discrete buckets

For example, you can separate orders into "Small", "Medium", or "Large" based on order amount:

    
CASE
    WHEN Amount < 20 THEN "Small"
    WHEN Amount >= 20 and Amount < 100 THEN "Medium"
    WHEN Amount >= 100 THEN "Large"
END

You can also use a Group calculated field to create ad hoc groups for dimension values.

Evaluate a logical AND condition

CASE 
    WHEN Country ISO Code = "US" AND Medium = "cpc" 
    THEN "US - Paid" 
    ELSE "other" 
END

Evaluate a logical AND/OR condition

CASE 
    WHEN REGEXP_MATCH(Video Title, ".*Google Analytics*")
    AND is_livestream = TRUE 
    OR Video Length > 600 
    THEN "GA Livestream or long video" 
END

Return a different field or value depending on a parameter value

Example 1: Return a dimension based on the parameter value selected. You can use this technique to let users switch the breakdown dimension used by a chart.

CASE 
    WHEN Breakdown = "Product Category" THEN Product Category 
    WHEN Breakdown = "Store" THEN Store 
END

Note that you could also write this using simple CASE syntax:

CASE Breakdown 
    WHEN "Product Category" THEN Product Category
    WHEN "Store" THEN Store
END

Example 2: Return a different metric based on a parameter value.

CASE WHEN Show Adjusted Cost = TRUE THEN Cost + Adjustments ELSE Cost END

Nested CASE statements

You can nest CASE statements to create more complex branching logic:

CASE WHEN REGEXP_CONTAINS(SKU, "Hats") THEN
    CASE WHEN Color = "blue"
        THEN "BLUE HAT" ELSE "JUST A HAT"
    END
    ELSE "NOT A HAT"
END

Related resources

• CASE (simple)
• Calculated fields
• Looker Studio function list
• google/RE2 Github documentation