Mysql 如何将表2从表1更新为表2中的相应条目？

我想统计不同表中银行的出现次数，并在FinalTable的相应列中进行更新

银行表：

  BankName  ErrorCode
    SBI         200
    ICICI       200
    SBI         400
    SBI         500
    SBI         503

ATMTable：

BankName    ErrorCode
ICICI       200
ICICI       400
ICICI       400
SBI         500
SBI         503

MitraTable：

BankName    ErrorCode
ICICI        200
ICICI        200
SBI          400
SBI          500
SBI          503
PNB          501  

财务报表：

BankName    BankCount   ATMCount    MitraCount  TotalCount
ICICI            1         3           2          6
SBI              4         2           3          9
PNB              0         0           1          1

---

我想计算不同银行的占用率，并在FinalTable中设置值。

您可以使用

UNION ALL

和条件聚合：

SELECT BankName,
       COUNT(CASE WHEN src = 'Bank' THEN 1 END) AS BankCount,
       COUNT(CASE WHEN src = 'ATM' THEN 1 END) AS ATMCount,
       COUNT(CASE WHEN src = 'Mitra' THEN 1 END) AS MitraCount,
       COUNT(*) AS TotalCount

FROM (
   SELECT BankName, 'Bank' AS src 
   FROM BankTable

   UNION ALL 

   SELECT BankName, 'ATM' AS src
   FROM ATMTable

   UNION ALL

   SELECT BankName, 'Mitra' AS src
   FROM MitraTable) AS t
GROUP BY BankName

字段

src

用于将源表返回到使用

UNION ALL

操作结果的外部查询。使用此字段，我们可以执行条件聚合，以统计每个源表中每个银行的发生率。

尝试以下操作：

SELECT BankName, 
       SUM(BankCount) AS BankCount, 
       SUM(ATMCount) AS ATMCount, 
       SUM(MitraCount) AS MitraCount, 
       SUM(BankCount + ATMCount + MitraCount) AS TotalCount 
FROM (SELECT BankName, 
             COUNT(ErrorCode) AS BankCount, 
             0 AS ATMCount, 
             0 AS MitraCount 
      FROM BankTable 
      GROUP BY BankName 
     UNION 
      SELECT BankName, 
             0 AS BankCount, 
             COUNT(ErrorCode) AS ATMCount, 
             0 AS MitraCount 
      FROM ATMTable 
      GROUP BY BankName 
     UNION 
      SELECT BankName, 
             0 AS BankCount, 
             0 AS ATMCount, 
             COUNT(ErrorCode) AS MitraCount 
      FROM MitraTable 
      GROUP BY BankName
    ) AS A
GROUP BY BankName;

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还包括其他RDBMS标记。。。使其成为MyStry。我删除了不兼容的数据库标记。请仅使用您实际使用的数据库标记问题。请阅读-总结是，这不是向志愿者提问的理想方式，可能会对获得答案产生反作用。请不要将此添加到您的问题中。