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

Try:

INSERT INTO orders(product_id, qty)
SELECT 2, 20 FROM products WHERE id = 2 AND qty_on_hand >= 20

If a product with id equal to 2 exists and the qty_on_hand is greater or equal to 20 for this product, then an insert will occur with the values product_id = 2, and qty = 20. Otherwise, no insert will occur.

Note: If your product ids are note unique, you might want to add a LIMIT clause at the end of the SELECT statement.