获取未知列错误，从子查询结果中获取列

Question

SELECT AID,DESCRIPTION,
IFNULL((SELECT SUM(DEBIT) FROM `GL_POSTED_TRANSACTION` WHERE AID = account.AID),0) AS PREV_DEBIT,
IFNULL((SELECT SUM(DEBIT) FROM `GL_POSTED_TRANSACTION` WHERE AID = account.AID),0) AS DEBIT 
FROM GL_ACCOUNT account 
WHERE CLASSID = 1 AND SUBCLASSID = 3
ORDER BY DESCRIPTION;

以上查询结果：   

但是当我添加 AND DEBIT＆gt; 0 我收到一条错误，说明未知栏DEBIT。

我做错了什么？有人可以解释一下。

Answer 1

在HAVING子句中添加该条件，而不是WHERE，例如;）

SELECT AID,DESCRIPTION,
IFNULL((SELECT SUM(DEBIT) FROM `GL_POSTED_TRANSACTION` WHERE AID = account.AID),0) AS PREV_DEBIT,
IFNULL((SELECT SUM(DEBIT) FROM `GL_POSTED_TRANSACTION` WHERE AID = account.AID),0) AS DEBIT 
FROM GL_ACCOUNT account 
WHERE CLASSID = 1 AND SUBCLASSID = 3
HAVING DEBIT > 0
ORDER BY DESCRIPTION;