Sql server 使用group by优化SQL Server连接查询

我只是想知道，下面给出的查询是否可以通过任何其他可行的方式实现，比如使用GROUPBY

        SELECT 
         GROUPMAS.GRPCODE, GROUPMAS.GRPNAME,
         GRPDTLS.ACCODE, GRPDTLS.ACNAME, GRPDTLS.DOA "ADMISSION DATE",
         LOANMAST.LOANCODE, LOANMAST.VCHDATE "LOAN SANCTION DATE", 
         LOANMAST.LANAMT,
         (SELECT SUM(RECPDTLS.INSTAMT) 
          FROM RECPDTLS 
          WHERE LOANCODE = LOANMAST.LOANCODE 
            AND RECPDTLS.VCHDATE <= '2009-03-31') AS REPAYMENT,
         (SELECT SUM(RECPDTLS.INTAMT) 
          FROM RECPDTLS 
          WHERE LOANCODE = LOANMAST.LOANCODE 
            AND RECPDTLS.VCHDATE <= '2009-03-31') AS INTREST,
         (SELECT MAX(RECPDTLS.VCHDATE) 
          FROM RECPDTLS 
          WHERE LOANCODE = LOANMAST.LOANCODE 
            AND RECPDTLS.VCHDATE <= '2009-03-31') AS "LAST PAYMENT ON"
     FROM 
         GROUPMAS
     JOIN 
         GRPDTLS ON (GROUPMAS.GRPCODE = GRPDTLS.GRPCODE AND GRPDTLS.DOA <= '2009-03-31')
     JOIN 
         LOANMAST ON (GRPDTLS.GRPCODE = LOANMAST.GRPCODE AND GRPDTLS.ACCODE = LOANMAST.ACCODE AND LOANMAST.VCHDATE <= '2009-03-31')

表GRPDTLS结构

GRPCODE | GRPNAME
--------| -------
1       | A
2       | B

GRPCODE | ACCODE | ACNAME | DOA 
--------|--------|--------|-----
1       | 1      | name1A | 2007-07-05
1       | 2      | name2A | 2008-07-05
2       | 1      | name1B | 2007-07-06
2       | 2      | name2B | 2007-07-05

LOANCODE | GRPCODE | ACCODE | VCHDATE  | LANAMT
---------|---------|--------|--------- |--------
1        | 1       | 2      |2009-01-06|2000
2        | 2       | 1      |2008-09-06|5000

TXNNO | LOANCODE | INSTAMT | INTAMT | VCHDATE
------|----------|---------|--------|---------
1     | 1        | 200     | 0      | 2009-02-06
2     | 1        | 200     | 10     | 2009-03-06
3     | 2        | 500     | 0      | 2008-10-06
4     | 2        | 1500    | 50     | 2009-03-28
5     | 2        | 500     | 0      | 2010-03-28

表LoanMaster结构

GRPCODE | GRPNAME
--------| -------
1       | A
2       | B

GRPCODE | ACCODE | ACNAME | DOA 
--------|--------|--------|-----
1       | 1      | name1A | 2007-07-05
1       | 2      | name2A | 2008-07-05
2       | 1      | name1B | 2007-07-06
2       | 2      | name2B | 2007-07-05

LOANCODE | GRPCODE | ACCODE | VCHDATE  | LANAMT
---------|---------|--------|--------- |--------
1        | 1       | 2      |2009-01-06|2000
2        | 2       | 1      |2008-09-06|5000

TXNNO | LOANCODE | INSTAMT | INTAMT | VCHDATE
------|----------|---------|--------|---------
1     | 1        | 200     | 0      | 2009-02-06
2     | 1        | 200     | 10     | 2009-03-06
3     | 2        | 500     | 0      | 2008-10-06
4     | 2        | 1500    | 50     | 2009-03-28
5     | 2        | 500     | 0      | 2010-03-28

表RECPDTLS结构

GRPCODE | GRPNAME
--------| -------
1       | A
2       | B

GRPCODE | ACCODE | ACNAME | DOA 
--------|--------|--------|-----
1       | 1      | name1A | 2007-07-05
1       | 2      | name2A | 2008-07-05
2       | 1      | name1B | 2007-07-06
2       | 2      | name2B | 2007-07-05

LOANCODE | GRPCODE | ACCODE | VCHDATE  | LANAMT
---------|---------|--------|--------- |--------
1        | 1       | 2      |2009-01-06|2000
2        | 2       | 1      |2008-09-06|5000

TXNNO | LOANCODE | INSTAMT | INTAMT | VCHDATE
------|----------|---------|--------|---------
1     | 1        | 200     | 0      | 2009-02-06
2     | 1        | 200     | 10     | 2009-03-06
3     | 2        | 500     | 0      | 2008-10-06
4     | 2        | 1500    | 50     | 2009-03-28
5     | 2        | 500     | 0      | 2010-03-28

它将输出如下内容

GRPCODE | GRPNAME | ACCODE | ACNAME | ADMISSION DATE | LOANCODE | LOAN SANCTION DATE | LANAMT | REPAYMENT | INTREST | LAST PAYMENT ON
--------| --------| -------| ------ | ---------------| -------- | ------------------ | -------| ----------| ------- | --------------
1       | A       | 2      | name2A | 2008-07-05     | 1        |2009-01-06          | 2000   | 400       | 10      | 2009-03-06
2       | B       | 1      | name1B | 2007-07-06     | 2        |2008-09-06          | 5000   | 2000      | 50      | 2009-03-28

---

感谢您的帮助。

您可以根据需要将select语句中的子查询替换为左外部联接或内部联接。如果所有LOANCODE记录都有匹配的RECPDTLS记录，则使用内部联接，否则使用左外部联接。保持聚合函数不变

 ...
 Repayment=SUM(RECPDTLS.INSTAMT),
 Interest=SUM(RECPDTLS.INTAMT),
 LastPaymentOn=MAX(RECPDTLS.VCHDATE) 
 ...
LEFT OUTER/INNER JOIN RECPDTLS ON RECPDTLS.LOANCODE = LOANMAST.LOANCODE AND  Repayment.VCHDATE <= @HighDate
 ...
 GROUP BY
     GROUPMAS.GRPCODE, GROUPMAS.GRPNAME,
     GRPDTLS.ACCODE, GRPDTLS.ACNAME, GRPDTLS.DOA,
     LOANMAST.LOANCODE, LOANMAST.VCHDATE, 
     LOANMAST.LANAMT

您需要运行查询分析器来查看新旧查询之间的效率增益

注意：如上所述，如果LOANCODE不需要RECPDTLS，请确保使用LET-OUTER-JOIN，因为内部连接只会在两个表中返回匹配项。

您可以使用以下方法简化请求：

;WITH LOANMASTAGG AS 
(
    SELECT SUM(r.INSTAMT) REPAYMENT, SUM(r.INTAMT) INTREST, MAX(r.VCHDATE) [LAST PAYMENT ON], l.LOANCODE, l.VCHDATE, l.LANAMT, l.ACCODE, l.GRPCODE
    FROM @RECPDTLS r
        INNER JOIN @LOANMAST l ON r.LOANCODE = l.LOANCODE
    WHERE  l.VCHDATE <= '2009-03-31'
    GROUP BY l.LOANCODE, l.VCHDATE, l.LANAMT, l.ACCODE, l.GRPCODE
)
SELECT 
         g.GRPCODE, 
         g.GRPNAME,
         gl.ACCODE, 
         gl.ACNAME, 
         gl.DOA "ADMISSION DATE",
         la.LOANCODE, 
         la.VCHDATE "LOAN SANCTION DATE", 
         la.LANAMT,
         la.REPAYMENT AS REPAYMENT,
         la.INTREST AS INTREST,
         la.[LAST PAYMENT ON] "LAST PAYMENT ON"
FROM LOANMASTAGG la
        INNER JOIN @GRPDTLS gl ON gl.GRPCODE = la.GRPCODE AND gl.ACCODE = la.ACCODE
        INNER JOIN @GROUPMAS g ON (g.GRPCODE = gl.GRPCODE)
WHERE gl.DOA <= '2009-03-31'

---

您可以添加当前查询的输出吗？一个建议是，您可以将三个子查询或还款、利息、上次付款放在一个查询中，并根据您需要的记录数进行联接或交叉应用。根据经验，如果您有多个子查询，都是从同一来源选择的，正如上面DVT所提到的，通常有一种方法可以合并它们。第二种方法工作得很好，速度也很快，但第一种方法产生了错误的列还款和利息结果，执行和返回5414行需要17秒，而所有其他查询都会在几毫秒内产生结果。无论如何，谢谢@ross bushI删除了第一个。它加入同一张桌子三次而不是一次。我意识到，在我看到每个聚合在联接表上都有相同的筛选器之后，所以您只需要一个联接。我感谢您的努力@ross bush，但我认为您应该再次编辑您的答案，as GROUP BY子句也是运行此查询所必需的。但是与RECPDTLS的左外部联接不会返回没有匹配RECPDTLS记录的LOANMAST的LOANCODE。那么，我们可以为这个问题做些什么呢？更新了答案，并添加了关于左外连接用法的注释。您也可以继续使用左外部联接，但是，在where子句中添加where NOT RECPDTLS.ID为NULL，这可能不是必需的。如果只需要匹配的记录，请使用和内部联接。