CASE defines one or more conditions and returns a result when a condition is met. You can define a default result if none of the conditions is met.
In this article:Example
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 expression like this:
CASE
WHEN Country IN ("USA","Canada","Mexico") THEN "North America"
WHEN Country IN ("England","France") THEN "Europe"
ELSE "Other"
END
How searched CASE works
A CASE expression begins with the CASE keyword and ends with the END keyword. In between, you'll have a number sections or "clauses":
- WHEN: a condition you want to evaluate. You can have multiple WHEN clauses in a single CASE expression.
- 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 expression.
- ELSE. Optional. If none of the WHEN clause conditions are true, CASE returns the value in the ELSE clause, or
NULLif 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.
Searched CASE syntax
CASE
WHEN condition THEN result
[WHEN condition THEN result]
[...]
[ELSE else_result]
END
Parameters
WHEN condition
WHEN conditions evaluate your data and return true if the specified condition is met, or false if it isn't. You can use any valid Boolean expression as the WHEN conditions.
THEN result
Each WHEN condition must have a matching THEN clause, which specifies the results if that condition is true. If there are multiple WHEN conditions, the CASE expression returns the result for the first true condition.
Notes
All of the possible results in a THEN clause must be of the same type.
For example, if the first THEN clause returns Text, additional THEN clauses, as well as the ELSE clause must also return Text.
ELSE else_result
The optional ELSE clause specifies a default result. This is returned if none of the WHEN clauses are true. If a CASE expression has no ELSE clause, and none of the WHEN clauses are true, the statement returns NULL. A CASE expression can only have 1 ELSE clause.
More examples
Check for inequality
CASE WHEN Medium != "cpc" THEN "free" ELSE "paid" END
Classify numeric dimension values into discrete buckets
For example, you can separate orders into Small, Medium, 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
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
Evaluate a parameter
For example, you can set a "Sales Target" parameter and adjust it to see which orders met the target:
CASE WHEN Qty Sold >= Sales target parameter THEN 1 ELSE 0 END
Return a different field or value depending on a parameter value
The first example returns a dimension based on the parameter value selected. You can use this technique to let users switch the breakdown dimension used by a chart.
The second example shows how to return a different metric based on a parameter value.
CASE
WHEN Breakdown = "Product Category" THEN Product Category
WHEN Breakdown = "Store" THEN Store
END
Note: you can also write this using simple CASE syntax:
CASE Breakdown
WHEN "Product Category" THEN Product Category
WHEN "Store" THEN Store
END
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 Color = "blue") THEN "BLUE HAT" ELSE "JUST A HAT" END
ELSE
"NOT A HAT"
END