Is there a difference between the two queries? Are both correct?
SET price = (SELECT buyPrice FROM products WHERE productCode = product);
SELECT buyPrice INTO price FROM products WHERE productCode = product;
>Solution :
Both are correct.
With the SET syntax, you can only set one variable at a time, so the SELECT query must have only one expression in its select-list.
With the SELECT INTO syntax, you can set multiple variables. For example:
SELECT buyPrice, lastUpdated INTO price, latest FROM products ...