MySQL INSERT IF (custom if statements)

Question

First, here\'s the concise summary of the question:

Is it possible to run an INSERT statement conditionally? Something akin to this:

IF(         


        

Answer 1

INSERT INTO TABLE
SELECT value_for_column1, value_for_column2, ...
FROM wherever
WHERE your_special_condition

If no rows are returned from the select (because your special condition is false) no insert happens.

Using your schema from question (assuming your id column is auto_increment):

insert into orders (product_id, qty)
select 2, 20
where (SELECT qty_on_hand FROM products WHERE id = 2) > 20;

This will insert no rows if there's not enough stock on hand, otherwise it will create the order row.

Nice idea btw!