MYSQL UNION SUM（量）出力2つの結果の代わりに1

Question

をJOIN私はこの下にあります。それが正常に動作するが、

SELECT a.* FROM (SELECT 
     asset_liability_income_expenditure_tbl.a_l_code, 
     SUM(mainaccount_a_2017.amount), mainaccount_a_2017.dr_cr_action 
     FROM `mainaccount_a_2017` LEFT JOIN chart_of_account 
     ON (
     chart_of_account.joint_account_numbers = 
     mainaccount_a_2017.joint_account_number 
     ) 
     LEFT JOIN asset_liability_income_expenditure_tbl 
     ON (
     asset_liability_income_expenditure_tbl.a_l_code = 
     chart_of_account.account_type 
    ) 
WHERE asset_liability_income_expenditure_tbl.a_l_code = 'FA' 
     AND mainaccount_a_2017.dr_cr_action = 'DR' UNION 
SELECT asset_liability_income_expenditure_tbl.a_l_code, 
SUM(mainaccount_b_2017.amount), 
mainaccount_b_2017.dr_cr_action 
FROM `mainaccount_b_2017` 
LEFT JOIN chart_of_account ON (
      chart_of_account.joint_account_numbers = 
      mainaccount_b_2017.joint_account_number 
    ) 
LEFT JOIN asset_liability_income_expenditure_tbl ON ( 
      asset_liability_income_expenditure_tbl.a_l_code = 
      chart_of_account.account_type 
    ) 
WHERE asset_liability_income_expenditure_tbl.a_l_code = 'FA' 
     AND mainaccount_b_2017.dr_cr_action = 'DR' 
) AS a 

ディスプレイのいずれか1つの空の上部に行と下和又はVIS-A- vis。私はLIMIT 1を試しましたが、行2のSUM（量）が出力され、フェッチできず、制限を適用しないと、行1のSUM（量）何が欠けているか知っている。親切にお手伝いください。ありがとう。

Answer 1

私はそれを理解しました。私は何かを反転させなければならなかった。下記の結果：

SELECT SUM(a) FROM 
(
    SELECT SUM(mainaccount_a_2017.amount) 
    AS a FROM `mainaccount_a_2017` 
    LEFT JOIN chart_of_account ON (chart_of_account.joint_account_numbers = mainaccount_a_2017.joint_account_number) 

    LEFT JOIN asset_liability_income_expenditure_tbl ON (asset_liability_income_expenditure_tbl.a_l_code = chart_of_account.account_type) 

    WHERE asset_liability_income_expenditure_tbl.a_l_code = 'FA' 
    AND mainaccount_a_2017.dr_cr_action = 'DR' 

    UNION ALL 

    SELECT SUM(mainaccount_b_2017.amount) 
    AS a FROM `mainaccount_b_2017` 
    LEFT JOIN chart_of_account ON (chart_of_account.joint_account_numbers = mainaccount_b_2017.joint_account_number) 

    LEFT JOIN asset_liability_income_expenditure_tbl ON (asset_liability_income_expenditure_tbl.a_l_code = chart_of_account.account_type) 

    WHERE asset_liability_income_expenditure_tbl.a_l_code = 'FA' AND mainaccount_b_2017.dr_cr_action = 'DR' 
) a