如何从 SQLyog 中的多个列中添加总计？

Question

SELECT DATE(DATE), 
       SUM(CASE WHEN pay_code = "AC" THEN amount ELSE 0 END) AS Cash,
       SUM(CASE WHEN pay_code = "BT" THEN amount ELSE 0 END) AS `Bank Transfer`,
       (Cash + `Bank Transfer`) AS Total 
FROM partial_payment
GROUP BY DATE(DATE);

当我运行这个查询时，我得到了这个错误： 错误代码：1054 “字段列表”中的未知列“现金”

SELECT DATE(date), 
       SUM(CASE WHEN pay_code = "AC" THEN amount ELSE 0 END) AS Cash,
       SUM(CASE WHEN pay_code = "BT" THEN amount ELSE 0 END) AS `Bank Transfer`,
       ('Cash' + 'Bank Transfer') AS Total 
FROM partial_payment
GROUP BY DATE(date);

当我像上面一样更改它时，它运行成功但总数不加起来

有人知道怎么解决吗？

Answer 1

您不能引用在同一选择列表中创建的列。相反，您可以使用 派生表（子查询）：

SELECT Cash, `Bank Transfer`, (Cash + `Bank Transfer`) AS Total 
FROM (
    SELECT DATE(DATE), 
           SUM(CASE WHEN pay_code = "AC" THEN amount ELSE 0 END) AS Cash,
           SUM(CASE WHEN pay_code = "BT" THEN amount ELSE 0 END) AS `Bank Transfer`
    FROM partial_payment
    GROUP BY DATE(DATE)
) dt

注意：('Cash' + 'Bank Transfer') 正在尝试添加字符串文字，并且 - 正如您所注意到的 - 返回完全不同的内容。