Question

I’m trying to create an SQL query in PHP to update a table.
Is it possible to have a different WHERE clause for each affected row?

eg something like:

UPDATE table 
SET val=X WHERE someproperty = 1,
SET val=Y WHERE someproperty = 2

etc?

Any help appreciated. Thanks

Answer 1

You cannot have multiple WHERE clauses for any SQL statement, however you can use a CASE statement to accomplish what you are trying to do. Another option that you have is to execute multiple UPDATE statements.

Here is a sample using the CASE statement:

UPDATE table
SET val = (
    CASE someproperty
        WHEN 1 THEN X
        WHEN 2 THEN Y
        ELSE val
    END
);

Here is a sample using multiple UPDATE statements:

UPDATE table SET val=X WHERE someproperty = 1;
UPDATE table SET val=Y WHERE someproperty = 2;