mysql - 在 MySQL 中执行 MINUS 操作不起作用

Question

SELECT m.inv_id,m.cus_id,CONCAT(c.customer_name ,', ', c.address) AS address,d.item_id,p.prod_name,d.quantity
FROM invoice_m m INNER JOIN customers c INNER JOIN invoice_d d INNER JOIN products p
WHERE m.cus_id = c.customer_id
AND m.inv_id = d.inv_id
AND d.item_id = p.prod_id
AND m.inv_id = 3
minus
SELECT m.inv_id,m.cus_id,m.cus_addr AS address,d.item_id,d.item_name AS prod_name,d.out_qty AS quantity 
FROM delivery_m m INNER JOIN delivery_d d 
WHERE m.inv_id = 3

我正在尝试执行 MySQL 减去查询不起作用。我需要减去 (qty - out_qty )，以便我可以获得实际的数量。

Answer 1

MySQL 不支持 MINUS 集合运算符。

所以像这样的查询

  SELECT x, y FROM table_a
  MINUS
  SELECT x, y FROM table_b;

在 MySQL 中变成:

SELECT a.x, a.y
FROM table_a a LEFT JOIN table_b b
ON a.x = b.x AND a.y = b.y
WHERE b.x IS NULL;