Unable to get left outer join result in mysql query

问题

  SELECT 
        BB.NAME BranchName,
        VI.NAME Village,
        COUNT(BAC.CBSACCOUNTNUMBER) 'No.Of Accounts',
        SUM(BAC.CURRENTBALANCE) SumOfAmount,
        SUM(CASE
            WHEN transactiontype = 'C' THEN amount
            ELSE 0
        END) AS CreditTotal,
        SUM(CASE
            WHEN transactiontype = 'D' THEN amount
            ELSE 0
        END) AS DebitTotal,
        SUM(CASE
            WHEN transactiontype = 'C' THEN amount
            WHEN transactiontype = 'D' THEN - 1 * amount
            ELSE 0
        END) AS CurrentBalance
    FROM
        CUSTOMER CU,
        APPLICANT AP,
        ADDRESS AD,
        VILLAGE VI,
        BANKBRANCH BB,
        BANKACCOUNT BAC
            LEFT OUTER JOIN
        accounttransaction ACT ON BAC.CBSACCOUNTNUMBER = ACT.BANKACCOUNT_CBSACCOUNTNUMBER
            AND ACT.TRANDATE <= '2013-03-21'
            AND BAC.ACCOUNTOPENINGDATE < '2013-03-21'
            AND ACT.BANKACCOUNT_CBSACCOUNTNUMBER IS NOT NULL
    WHERE
        CU.CODE = AP.CUSTOMER_CODE
            AND BAC.ENTITY = 'CUSTOMER'
            AND BAC.ENTITYCODE = CU.CODE
            AND AD.ENTITY = 'APPLICANT'
            AND AD.ENTITYCODE = AP.CODE
            AND AD.VILLAGE_CODE = VI.CODE
            AND AD.STATE_CODE = VI.STATE_CODE
            AND AD.DISTRICT_CODE = VI.DISTRICT_CODE
            AND AD.BLOCK_CODE = VI.BLOCK_CODE
            AND AD.PANCHAYAT_CODE = VI.PANCHAYAT_CODE
            AND CU.BANKBRANCH_CODE = BB.CODE
            AND BAC.CBSACCOUNTNUMBER IS NOT NULL
            AND ACT.TRANSACTIONTYPE IS NOT NULL
    GROUP BY BB.NAME , VI.NAME;

Here is my information I have two tables bankaccount and accountransactions table If account is created it will go to bankaccount table and if any transaction is done so respective account number record in accounttrasactiosns table however I want to display the count of total account numbers respective to the branch which the account number existed in bankaccount and it is may or may not available in accounttransactions table.

回答1:

I'm guessing that the problem you have is that you are not getting results for accounts that do not have data in your accounttransaction table, even though you are using a LEFT JOIN. If that is true, the reason is because your join condition includes AND ACT.BANKACCOUNT_CBSACCOUNTNUMBER IS NOT NULL, which defeats the LEFT JOIN. You also have two conditions in your WHERE clause that I bet should not be there.

You should learn to use explicit join syntax in your coding. Your code will be much clearer if you do that; it separates the join conditions from the WHERE clause, which does a very different thing. I took a stab at re-writing your query as an illustration:

SELECT
    BB.NAME BranchName,
    VI.NAME Village,
    COUNT(BAC.CBSACCOUNTNUMBER) 'No.Of Accounts',
    SUM(BAC.CURRENTBALANCE) SumOfAmount,
    SUM(ACT.CurrentBalance) CurrentBalance,
    SUM(ACT.DebitTotal) DebitTotal,
    SUM(ACT.CreditTotal) CreditTotal

FROM   CUSTOMER CU

JOIN   APPLICANT AP
ON     AP.CUSTOMER_CODE = CU.CODE

JOIN   ADDRESS AD
ON     AD.ENTITYCODE = AP.CODE

JOIN   VILLAGE VI
ON     VI.CODE           = AD.VILLAGE_CODE
   AND VI.STATE_CODE     = AD.STATE_CODE
   AND VI.DISTRICT_CODE  = AD.DISTRICT_CODE
   AND VI.BLOCK_CODE     = AD.BLOCK_CODE
   AND VI.PANCHAYAT_CODE = AD.PANCHAYAT_CODE

JOIN   BANKBRANCH BB
ON     BB.CODE = CU.BANKBRANCH_CODE

JOIN   BANKACCOUNT BAC
ON     BAC.ENTITYCODE = CU.CODE

LEFT OUTER JOIN (
   SELECT BANKACCOUNT_CBSACCOUNTNUMBER,
          SUM(CASE
             WHEN transactiontype = 'C' THEN amount
             ELSE 0
             END) AS CreditTotal,
          SUM(CASE
             WHEN transactiontype = 'D' THEN amount
             ELSE 0
             END) AS DebitTotal,
          SUM(CASE
             WHEN transactiontype = 'C' THEN amount
             WHEN transactiontype = 'D' THEN - 1 * amount
             ELSE 0
             END) AS CurrentBalance
   FROM    accounttransaction
   WHERE   TRANDATE <= '2013-03-21'
   GROUP BY BANKACCOUNT_CBSACCOUNTNUMBER
   ) ACT

ON     ACT.BANKACCOUNT_CBSACCOUNTNUMBER = BAC.CBSACCOUNTNUMBER
   AND BAC.ACCOUNTOPENINGDATE < '2013-03-21'

WHERE  BAC.ENTITY = 'CUSTOMER'
   AND AD.ENTITY = 'APPLICANT'

GROUP BY BB.NAME , VI.NAME;

I removed this line from the LEFT JOIN condition

AND ACT.BANKACCOUNT_CBSACCOUNTNUMBER IS NOT NULL

And I removed these two lines from the WHERE clause

AND BAC.CBSACCOUNTNUMBER IS NOT NULL
AND ACT.TRANSACTIONTYPE IS NOT NULL

If that does not solve your problem, please revise your question to explain further.

UPDATE: Based on comments, the query is revised to calculate the debit, credit, and current balance by account using a derived table.

Also note the placement of the BAC.ACCOUNTOPENINGDATE < '2013-03-21' condition on left join. As written, this will return all accounts regardless of the opening date. If you want to only show accounts that were opened before that date, this condition should be moved to the WHERE clause.

来源：https://stackoverflow.com/questions/17277899/unable-to-get-left-outer-join-result-in-mysql-query