c# - 组合来自不同表的多个 Select 语句

Question

我有这个 MYSQL SP，它对不同的表进行求和，但我希望 SP 返回一个表一行中的所有结果，我尝试使用 + 组合来自选择的结果，但出现错误

 DROP PROCEDURE IF EXISTS x.GetFinanceContent;
 delimiter //
 CREATE PROCEDURE x.GetFinanceContent
    (
         IN  userId INT

    )
 BEGIN
 (SELECT SUM(AMOUNT) AS creditTotal
    FROM x.Card1 
    WHERE user_Id = userId and card_type=1) 
    +

 (SELECT SUM(AMOUNT) AS debitTotal
    FROM x.Card2 
    WHERE user_Id = userId and card_type=2) 


 END;//

Error Code: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '+ (SELECT SUM(AMOUNT) AS debitTotal FROM x.Card WHERE user_Id ' at line 10 0.000 sec

Answer 1

SELECT 
    ( SELECT SUM(AMOUNT) AS creditTotal
      FROM x.Card1
      WHERE user_Id = userId AND card_type=1
    )  
  , ( SELECT SUM(AMOUNT) AS debitTotal
      FROM x.Card2
      WHERE user_Id = userId AND card_type=2
    )