慢SQL查询返回 - 如何获得更好的结果？

Question

我被要求编写一个只返回具有特定操作代码（内部名称）的帐户的查询。有6个代码必须在帐户上，并且不能有其他代码可用。该表存储在一个名为tblTrans表（见下文）：

AccountNo ActionCode TransactionNo 
1234  Code1  45646453 
1234  Code2  88758475 
1234  Code3  48978978 
1234  Code4  15687898 
1234  Code5  59878988 
1234  Code6  12345677 
2548  Code1  45464533 
2548  Code2  89789489 
2548  Code3  89789781 
2548  Code4  16878983 
2548  Code5  59889884 
2548  Code6  12456776 
2548  Code12  12348887 

因此所需的输出将只返回帐户1234

目前这正与查询做过类似

SELECT AccountNo, ActionCode, TransactionNo  
FROM tblTrans AS t1 
INNER JOIN 
     tblTrans AS t2 ON t1.AccountNo = t2.AccountNo 
     tblTrans AS t3 ON t2.AccountNo = t3.AccountNo 
     tblTrans AS t4 ON t3.AccountNo = t4.AccountNo 
     tblTrans AS t5 ON t4.AccountNo = t5.AccountNo 
     tblTrans AS t6 ON t5.AccountNo = t6.AccountNo 
WHERE t1.ActionCode = 'Code1' 
    AND t2.ActionCode = 'Code2' 
    AND t3.ActionCode = 'Code3' 
    AND t4.ActionCode = 'Code4' 
    AND t5.ActionCode = 'Code5' 
    AND t5.ActionCode = 'Code6' 
    AND t6.AccountNo NOT IN (SELECT ActionCode 
          FROM tblTrans 
          WHERE ActionCode IN ('Code12')) 

对不起，如果语法出来了，我不得不为了安全原因改变一些细节！

这实际上运行非常缓慢，扼流系统很少。我的问题是，是否有更好的方式来编写这种类型的查询。我对CTE的了解不多，但听起来似乎适合？

Answer 1

这应该返回AccountNo的只有你想要的代码。

SELECT AccountNo 
FROM tblTrans 
GROUP BY AccountNo 
HAVING Sum(Case When ActionCode = 'Code1' Then 1 End) > 0 
     And Sum(Case When ActionCode = 'Code2' Then 1 End) > 0 
     And Sum(Case When ActionCode = 'Code3' Then 1 End) > 0 
     And Sum(Case When ActionCode = 'Code4' Then 1 End) > 0 
     And Sum(Case When ActionCode = 'Code5' Then 1 End) > 0 
     And Sum(Case When ActionCode = 'Code6' Then 1 End) > 0 
     And Sum(Case When ActionCode IN ('Code1', 'Code2', 'Code3', 'Code4', 'Code5', 'Code6') Then 0 Else 1 End) = 0 

我修改了查询。这一个应该表现更好。如果性能仍然不可接受，那么您应该考虑在表中添加索引。

要恢复所有的数据...

; With FilteredData As 
(
    SELECT AccountNo 
    FROM tblTrans 
    GROUP BY AccountNo 
    HAVING Sum(Case When ActionCode = 'Code1' Then 1 End) > 0 
      And Sum(Case When ActionCode = 'Code2' Then 1 End) > 0 
      And Sum(Case When ActionCode = 'Code3' Then 1 End) > 0 
      And Sum(Case When ActionCode = 'Code4' Then 1 End) > 0 
      And Sum(Case When ActionCode = 'Code5' Then 1 End) > 0 
      And Sum(Case When ActionCode = 'Code6' Then 1 End) > 0 
      And Sum(Case When ActionCode IN ('Code1', 'Code2', 'Code3', 'Code4', 'Code5', 'Code6') Then 0 Else 1 End) = 0 
) 
Select TblTrans.AccountNo, ActionCode, TransactionNumber 
From TblTrans 
     Inner Join FilteredData 
      On tblTrans.AccountNo = FilteredData.AccountNo