SQL UNION 查询不起作用

Question

这是我当前的查询：

1

SELECT FilteredInvoice.accountidname, 
       FilteredInvoice.createdon, 
       FilteredInvoice.createdon AS sort_date, 
       FilteredInvoice.duedate, 
       FilteredInvoice.invoicenumber, 
       FilteredInvoice.statecodename, 
       FilteredInvoice.totalamount_base, 
       CONVERT(datetime, NULL) AS mag_paymentdate, 
       0 AS mag_amount_base, 
       GETDATE() AS Today
  FROM FilteredAccount AS CRMAF_FilteredAccount 
  JOIN FilteredInvoice ON FilteredInvoice.accountid = CRMAF_FilteredAccount.accountid 
  JOIN FilteredMag_Payment ON FilteredInvoice.invoiceid = FilteredMag_Payment.mag_invoiceid
 WHERE (FilteredInvoice.statecodename <> 'Canceled')

2

   SELECT FilteredInvoice_1.accountidname, 
          FilteredInvoice_1.createdon, 
          FilteredInvoice_1.createdon AS sort_date, 
          FilteredInvoice_1.duedate, 
          FilteredInvoice_1.invoicenumber, 
          FilteredInvoice_1.statecodename, 
          FilteredInvoice_1.totalamount_base, 
          FilteredMag_Payment.mag_paymentdate, 
          FilteredMag_Payment.mag_amount_base, 
          GETDATE() AS Today
     FROM FilteredAccount AS CRMAF_FilteredAccount 
LEFT JOIN FilteredInvoice AS FilteredInvoice_1 ON FilteredInvoice_1.accountid = CRMAF_FilteredAccount.accountid 
     JOIN FilteredMag_Payment ON FilteredInvoice_1.invoiceid = FilteredMag_Payment.mag_invoiceid
    WHERE (FilteredInvoice_1.statecodename <> 'Canceled')

这些单独执行的操作正是我想要的，但是一旦我尝试使用“UNION”或“子查询”连接它们，第二个查询总是会中断并显示错误的信息。

我只是金发碧眼无法解决这个问题还是我实际上做错了什么。

感谢所有帮助。

非常感谢西蒙。

编辑： 我所说的“错误信息”是指第二个查询返回所有值，而不是遵循 CRMAF_ 前缀并仅返回其运行帐户中的值。

Answer 1

很难猜测“错误信息”是什么意思，但我相信您想要 UNION ALL 而不是 UNION。

UNION 会删除重复项，因此如果第一个查询之前返回了第二个查询中的记录，则不会返回这些记录。此外，一个查询中可能的重复项也将被消除。

UNION 中的记录数可以少于两个查询中的记录总数。

如果您只想连接两个记录集，请使用 UNION ALL：

SELECT FilteredInvoice.accountidname, 
       FilteredInvoice.createdon, 
       FilteredInvoice.createdon AS sort_date, 
       FilteredInvoice.duedate, 
       FilteredInvoice.invoicenumber, 
       FilteredInvoice.statecodename, 
       FilteredInvoice.totalamount_base, 
       CONVERT(datetime, NULL) AS mag_paymentdate, 
       0 AS mag_amount_base, 
       GETDATE() AS Today
  FROM FilteredAccount AS CRMAF_FilteredAccount 
  JOIN FilteredInvoice ON FilteredInvoice.accountid = CRMAF_FilteredAccount.accountid 
  JOIN FilteredMag_Payment ON FilteredInvoice.invoiceid = FilteredMag_Payment.mag_invoiceid
 WHERE (FilteredInvoice.statecodename <> 'Canceled')
UNION ALL
   SELECT FilteredInvoice_1.accountidname, 
          FilteredInvoice_1.createdon, 
          FilteredInvoice_1.createdon AS sort_date, 
          FilteredInvoice_1.duedate, 
          FilteredInvoice_1.invoicenumber, 
          FilteredInvoice_1.statecodename, 
          FilteredInvoice_1.totalamount_base, 
          FilteredMag_Payment.mag_paymentdate, 
          FilteredMag_Payment.mag_amount_base, 
          GETDATE() AS Today
     FROM FilteredAccount AS CRMAF_FilteredAccount 
LEFT JOIN FilteredInvoice AS FilteredInvoice_1 ON FilteredInvoice_1.accountid = CRMAF_FilteredAccount.accountid 
     JOIN FilteredMag_Payment ON FilteredInvoice_1.invoiceid = FilteredMag_Payment.mag_invoiceid
    WHERE (FilteredInvoice_1.statecodename <> 'Canceled')

Answer 2

在我看来，您应该能够获得与 UNIONed 查询相同的结果，其中包含以下内容：

   SELECT FilteredInvoice_1.accountidname, 
          FilteredInvoice_1.createdon, 
          FilteredInvoice_1.createdon AS sort_date, 
          FilteredInvoice_1.duedate, 
          FilteredInvoice_1.invoicenumber, 
          FilteredInvoice_1.statecodename, 
          FilteredInvoice_1.totalamount_base, 
          CASE PF.pay_flag 
              WHEN 0.0 THEN CONVERT(datetime, NULL)
              ELSE FilteredMag_Payment.mag_paymentdate
          END AS mag_paymentdate, 
          FilteredMag_Payment.mag_amount_base * PF.pay_flag AS mag_amount_base, 
          GETDATE() AS Today
     FROM FilteredAccount AS CRMAF_FilteredAccount 
     CROSS JOIN (SELECT 1.0 pay_flag UNION SELECT 0.0) AS PF
     JOIN FilteredInvoice AS FilteredInvoice_1 ON FilteredInvoice_1.accountid = CRMAF_FilteredAccount.accountid 
     LEFT JOIN FilteredMag_Payment ON FilteredInvoice_1.invoiceid = FilteredMag_Payment.mag_invoiceid
    WHERE (FilteredInvoice_1.statecodename <> 'Canceled') AND
          (PF.pay_flag = 0 OR FilteredMag_Payment.mag_invoiceid IS NOT NULL)

编辑：LEFT JOIN FilteredMag_Payment

进一步编辑：将最后的括号 OR 条件添加到 WHERE 子句。