1

我有一个这样的sql查询......

SELECT c.clientid, c.clientname, c.billingdate, 
       (SELECT ifnull(sum(total), 0) 
          FROM invoice i
         WHERE i.client = c.clientid AND i.isdeleted = 0) -
       (SELECT ifnull(sum(p.amount), 0) 
          FROM payment p
         INNER JOIN invoice i ON p.invoice = i.invoiceid
         WHERE i.client = c.clientid and i.isdeleted = 0) as balance, 
        CASE c.isactive+0 WHEN '1' THEN 'Stop'
                                   ELSE 'Start' END as Active
FROM client c
ORDER BY clientname

这工作正常，没有错误，但请注意这部分....

(SELECT ifnull(sum(total), 0) 
          FROM invoice i
         WHERE i.client = c.clientid AND i.isdeleted = 0) -(SELECT ifnull(sum(p.amount), 0) 
   FROM payment p
  INNER JOIN invoice i ON p.invoice = i.invoiceid
  WHERE i.client = c.clientid AND i.isdeleted = 0) as balance

我写了一个PHP脚本...

if($remaining < 0){
    $remaining = $row['total'];
}else{
    $remaining = $remaining + $row['total'];
}

我想要做的是将我在 PHP 中编写的内容合并到我的 SQL 查询中，但我之前从未使用 if 语句编写过 SQL 查询（如果允许的话）。如何将我的 PHP 脚本合并到我的 SQL 查询中？有什么建议么？

4

2 回答 2

2

没有if，但是有case它可以让你做几乎相同的事情。您已经case在查询中使用了 a，所以我想您知道它是如何工作的。:)

于 2012-09-04T19:00:40.230 回答
1

您可以包装您的结果并使用它。确保总数和剩余是结果的一部分。

SELECT tt.clientid, tt.clientname, tt.billingdate, tt.total, tt.remaining, tt.active 
  FROM (
            ... here goes all of your select but the the order by 
       ) tt
ORDER BY tt.clientid

有了这个结构，你可以做你在 PHP 中所做的事情

SELECT tt.clientid, tt.clientname, tt.billingdate, tt.total, tt.active,
       CASE WHEN tt.remaining < 0 then tt.total
                                  else tt.remaining - tt.total
            END as remaining
  FROM (
            ... here goes all of your select make sure you select a total and a remaining
       ) tt
ORDER BY tt.clientid

所以你要做的是实际创建一个临时视图。不确定您的数据模型，但我认为看起来像这样

SELECT tt.clientid, tt.clientname, tt.billingdate, tt.total, tt.active,
       CASE WHEN tt.remaining < 0 then tt.total
                                  else tt.remaining - tt.total
            END as remaining
 FROM (
    SELECT c.clientid, c.clientname, c.billingdate, 
       (SELECT ifnull(sum(total), 0) 
          FROM invoice i
         WHERE i.client = c.clientid AND i.isdeleted = 0) as total,
       (SELECT ifnull(sum(total), 0) 
          FROM invoice i
         WHERE i.client = c.clientid AND i.isdeleted = 0) -
       (SELECT ifnull(sum(p.amount), 0) 
          FROM payment p
         INNER JOIN invoice i ON p.invoice = i.invoiceid
         WHERE i.client = c.clientid and i.isdeleted = 0) as remaining, 
        CASE c.isactive+0 WHEN '1' THEN 'Stop'
                                   ELSE 'Start' END as Active
      FROM client c
      ) TT
ORDER BY clientname
于 2012-09-04T19:00:29.377 回答