CASE keyword
Syntax
Description
CASE goes through a set of conditions and returns a value corresponding to the
first condition met. Each new condition follows the WHEN condition THEN value
syntax. The user can define a return value when no condition is met using
ELSE. If ELSE is not defined and no conditions are met, then case returns
null.
Examples
Assume the following data
| name | age |
|---|---|
| Tom | 4 |
| Jerry | 19 |
| Anna | 25 |
| Jack | 8 |
CASE with ELSE
SELECT
name,
CASE
WHEN age > 18 THEN 'major'
ELSE 'minor'
END
FROM my_table
Result
| name | case |
|---|---|
| Tom | minor |
| Jerry | major |
| Anna | major |
| Jack | minor |
CASE without ELSE
SELECT
name,
CASE
WHEN age > 18 THEN 'major'
END
FROM my_table
Result
| name | case |
|---|---|
| Tom | null |
| Jerry | major |
| Anna | major |
| Jack | null |