SQL 查詢從一個表求和到另一個表

Question

我有兩張桌子：

What I needs is SQL query that I can run via the SQL tab in phpMyAdmin, which will sum the "options_stock" from "table_options" based on the "product_id", and it will write that sum number into "main_stock" in "table_products"對於相應的“product_id”，因此“table_products”將如下所示：

提前致謝。

Answer 1

試試下面的 - 更新加入

update table_product p  
join 
(select product_id, sum(options_stock) as options_stock from
table_options group by product_id
) o on p.product_id=o.product_id
set main_stock=options_stock