Question

我有以下sql查询来了解它的作用请阅读下面的描述

select catalogid, numitems, allitems - numitems ignoreditems
    from (
      select i.catalogid,
        sum(case when (ocardtype in ('PayPal','Sofort') OR
                       ocardtype in ('mastercard','visa') and
                       odate is not null) AND NOT EXISTS (
                         select * from booked b
                         where b.ignoredoid = o.orderid
                       ) then numitems
                       else 0 end) numitems,
        sum(numitems) allitems
      from orders o
      join oitems i on i.orderid=o.orderid
      group by i.catalogid
    ) X

和以下sql表

oitems表

+---------+-----------+----------+
| orderid | catalogid | numitems |
+---------+-----------+----------+
| O737    |       353 |        1 |
| O738    |       364 |        4 |
| O739    |       353 |        3 |
| O740    |       364 |        6 |
| O741    |       882 |        2 |
| O742    |       224 |        5 |
| O743    |       224 |        2 |
+---------+-----------+----------+

订单表

 +-----------------+------------+------------+
    |         orderid | ocardtype  |   odate    |
    +-----------------+------------+------------+
    |     O737        | Paypal     |            | 'OK
    |     O738        | MasterCard | 01.02.2012 | 'OK
    |     O739        | MasterCard | 02.02.2012 | 'OK
    |     O740        | Visa       | 03.02.2012 | 'OK
    |     O741        | Sofort     |            | 'OK
    |     O742        |            |            | 'ignore because ocardtype is empty
    |     O743        | MasterCard |            | 'ignore because Mastercard no odate
    +-----------------+------------+------------+

重新声明的数据表

+-----------+----------+--------------+
| catalogid | numitems | ignoreditems |
+-----------+----------+--------------+
|       353 |        4 |            0 |
|       364 |       10 |            0 |
|       882 |        2 |            0 |
|       224 |        0 |            7 |
+-----------+----------+--------------+

想法是将具有相同catalogid描述的产品的numitems列与oitems表中的数据相加并具有以下条件

如果ocardtype为空，则忽略numitems并将其视为0 在总和中将被忽略的项目汇总到ignoreditems列
如果某个订单的ocardtype是万事达卡或Visa，odate是为空，然后忽略numitems并将其视为0并将其相加忽略了ignoreditems列
如果ocardtype是Paypal或Sofort，那么只需要numitems总和不检查odate，因为这些类型不需要odate
在另一个叫做预订的表中我有一个名为ignoredoid的列，这列包含我想要的上表中的orderids 即使上面的3个条件是满意的，也要忽略

到目前为止，查询工作完全归功于@Richard aka cyberkiwi对此问题的回答question

问题是，我需要结果数据表看起来像下面的

+-----------+----------+--------------+-------------------+
| catalogid | numitems | ignoreditems | orderidcollection |
+-----------+----------+--------------+-------------------+
|       353 |        4 |            0 | O737,O739         |
|       364 |       10 |            0 | O738,O740         |
|       882 |        2 |            0 | O741              |
|       224 |        0 |            7 |                   |'O742 & O743 are ignored      
+-----------+----------+--------------+-------------------+

正如您所看到的唯一更改是添加了orderidcollection列，只有在代码中未忽略该顺序时，才必须将orderid添加到由逗号分隔的新列中，我一直在谷歌搜索几个小时没有运气！这甚至可以用SQL吗？

Answer 1

我的Linq-to-Sql对您之前的问题的回答扩展到此问题（LINQpad查询）：

Dim odateRequired = {"MasterCard", "Visa"}
Dim odateNotRequired = {"Paypal", "Sofort"}

Dim result = From o In Orders Join i In Oitems On o.orderid Equals i.orderid _
             Let check = Not (From b In Bookeds Where b.ignoredoid=i.orderid).Any _
                     AndAlso o.ocardtype IsNot Nothing _
                     AndAlso ((odateRequired.Contains(o.ocardtype) AndAlso o.odate IsNot Nothing) _
                        OrElse odateNotRequired.Contains(o.ocardtype)) _
         Group By i.catalogid Into _
         numitems = Sum(If(check, i.numitems, 0)), _
         ignoreditems = Sum(If(check, 0, i.numitems)), _
         group
         Select catalogid, numitems, ignoreditems, _
             orderidcollection = String.Join(",", (From g in group Where g.check Select g.i.orderid))
result.Dump

请注意，此解决方案会发出多个SQL查询，以确定每个orderids的{{1}}，其中catalogid为check以累积每个True。可能有一个更有效的解决方案（使用一些，可能是复杂的Linq-to-Sql，导致生成的SQL执行相当于orderidcollection，或者使用Linq-to-Sql获取String.Join然后使用Linq-to-objects进行最终累积。）

另请注意，此查询包含您的catalogid, numitems, check, orderid表（LINQpad的复数形式）。

SQL将处理后的id添加到用逗号分隔的单个单元格中

1 个答案: