MySql Select Query - 从 WHERE 子句获取错误

Question

我是 MySQL 新手。

SELECT
     receive_item.RECEIPT_ID,
     receive_item.ITEM_ID, 
     (receive_item.QTY - delivery_item.QTY) AS QtyRemained 
FROM receive_item
INNER JOIN delivery_item
ON receive_item.ITEM_ID = delivery_item.ITEM_ID 
AND receive_item.RECEIPT_ID = delivery_item.RECEIVE_ID

这是上面查询的结果

RECEIPT_ID ITEM_ID  QTYRemained
    1         1         0
    2         2         0
    3         3         1
    4         4         0
    5         5         0

我只想显示 QTYRemained 值不为 0 的行。像这样

RECEIPT_ID ITEM_ID  QTYRemained
    3         3         1

在上面的选择查询末尾添加“From QTYRemained != 0”时出现错误。有人可以告诉我为什么它不起作用吗？

Answer 1

在最后添加

WHERE QtyRemained > 0

所以...

SELECT
     receive_item.RECEIPT_ID,
     receive_item.ITEM_ID, 
     (receive_item.QTY - delivery_item.QTY) AS QtyRemained 
FROM receive_item
INNER JOIN delivery_item
ON receive_item.ITEM_ID = delivery_item.ITEM_ID 
AND receive_item.RECEIPT_ID = delivery_item.RECEIVE_ID
WHERE QtyRemained > 0