Mysql – Updating multiple rows with different values in one query

MySQLupdate

I am trying to understand how to UPDATE multiple rows with different values and I just don't get it. The solution is everywhere but to me it looks difficult to understand.

For instance, two updates into 1 query:

UPDATE mytable SET fruit='orange', drink='water', food='pizza' WHERE id=1;

UPDATE mytable SET fruit='strawberry', drink='wine', food='fish' WHERE id=2;

I don't understand what the CASE WHEN .. THEN … END works and how to use it.

Wonder if someone could help me on this.

Best Answer

UPDATE mytable SET
    fruit = CASE WHEN id=1 THEN 'orange' ELSE 'strawberry' END,
    drink = CASE WHEN id=1 THEN 'water'  ELSE 'wine'       END,
    food  = CASE WHEN id=1 THEN 'pizza'  ELSE 'fish'       END
WHERE id IN (1,2);

Personally, using CASE WHEN THEN END looks clumsy.

You could code this using the IF function.

UPDATE mytable SET
    fruit = IF(id=1,'orange','strawberry'),
    drink = IF(id=1,'water','wine'),
    food  = IF(id=1,'pizza','fish')
WHERE id IN (1,2);

Give it a Try !!!

CAVEAT : CASE WHEN THEN END is only handy when dealing with multiple values (more than 2)

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