Mysql implements two-Table Association updates

The basic update syntax is to update the table set field = value where field = xxx

Existing Material Table materials (y_name, y_quantity), product Table a (p_name, p_quantity), to summarize the materials used by product a to materials

Mysql is not applicable to a method used for associating with the Internet.

Select a. p_quantity + m. y_quantity + B. p_quantity from materials m, pro_a, pro_ B B where a. p_name = m. y_name and B. p_name = m. y_name;

It should be written like this:

Update materials m left join pro_a on m. y_name = a. p_name set m. y_quantity = a. p_quantity + m. y_quantity;