mysql - 与SQL中派生列的区别

我有一个查询。我将两个列的值添加到一个派生的列，然后我想从派生的列和已经存在的列中求出差值。
但是我遇到了一些未知的列错误

 SELECT  `st_id` ,  `fee` , SUM(  `total` ) AS total, SUM(  `books` ) AS book,SUM(  `uniform` ) AS uniform,SUM(  `total` + `books` + `uniform` ) AS amount,SUM(  `amount` - `paid` ) AS pending
  FROM  `fee_tbl`
  WHERE  `st_id`
  IN ( 40, 504, 533, 640, 817, 944 )
  GROUP BY  `fee` ,  `st_id`

有人知道怎么了吗？

最佳答案

如果要为特定的amount和pending查找fee和st_id

然后

SELECT
    `st_id` ,
    `fee` ,
    SUM(  `total` ) AS total,
    SUM(  `books` ) AS book,
    SUM(  `uniform` ) AS uniform,
    SUM(  `total` + `books` + `uniform` ) AS amount,
    SUM(  `total` + `books` + `uniform` - `paid` ) AS pending
FROM  `fee_tbl`
WHERE  `st_id` IN ( 40, 504, 533, 640, 817, 944 )
GROUP BY  `fee` ,  `st_id`

要么

SELECT
    `st_id` ,
    `fee` ,
    SUM(  `total` ) AS total,
    SUM(  `books` ) AS book,
    SUM(  `uniform` ) AS uniform,
    SUM(  `total` ) + SUM(  `books` ) + SUM(  `uniform` ) AS amount,
    SUM(  `total` ) + SUM(  `books` ) + SUM(  `uniform` ) - SUM(`paid` ) AS pending
FROM  `fee_tbl`
WHERE  `st_id` IN ( 40, 504, 533, 640, 817, 944 )
GROUP BY  `fee` ,  `st_id`