mySQL——正确的方法吗？

我想你可以，我是个老混蛋，但多年来我自己都不是专家，我很确定有更好的方法来写这篇文章。希望你能在这方面帮助我

SELECT
    (SELECT MIN(bank_id) FROM bank) AS MinBank,
    (SELECT MAX(bank_id) FROM bank) AS MaxBank,
    (SELECT bank_id FROM bank WHERE bank_id = $UserID) AS OldBankID,
    (SELECT bank_name FROM bank WHERE bank_id = OldBankID) AS OldBankName,
    (SELECT bank_interest FROM bank WHERE bank_id = OldBankID) AS OldBankInterest,
    (SELECT bank_fees FROM bank WHERE bank_id = OldBankID) AS OldBankFees,
    (SELECT bank_pic_url FROM bank WHERE bank_id = OldBankID) AS BankPic
    (SELECT bank_id FROM bank HAVING bank_id > (SELECT bank_id FROM users WHERE uid = $UserID) LIMIT 1) AS NewBankID,
    (SELECT bank_name FROM bank WHERE bank_id = NewBankID) AS NewBankName,
    (SELECT bank_interest FROM bank WHERE bank_id = NewBankID) AS NewBankInterest,
    (SELECT bank_fees FROM bank WHERE bank_id = NewBankID) AS NewBankFees,
    (SELECT bank_cost FROM bank WHERE bank_id = NewBankID) AS NewBankCost,
FROM dwrel_bank LIMIT 1

基本上是两张表： 用户表1-检索银行ID客户的旧ID 银行表2-获取其旧银行信息并检索其下一次升级可用性

它确实给了我想要的信息，但我想看看我是否能以某种方式改进它

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谢谢

您可以根据oldBankId更改第一部分，如下所示

 select bank_id OldBankId ,bank_name OldBankName, bank_interest OldBankInterest ,
 bank_fees OldBankFees, bank_pic_url as BankPic from bank
 where bank_Id =(select bank_id from bank where bank_id= $user_id)

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您必须将其与新银行Id连接起来，并使用与上述相同的语法

这让人困惑，在一个地方，您从银行表中获取旧银行Id，在另一个地方，您从用户表中获取旧银行Id基本上是这样的：从用户表中获取银行Id。然后使用此银行id并从银行表中获取信息。然而，从银行表中，我需要来自同一银行表的两个重复信息：他们当前的银行信息和他们下一次可能的升级。当你说加入时，你是指联合还是左加入？不太确定。使用left join on id=从表中选择id，其中id>$userId limit 1希望您能指路，我自己尝试时有点迷路了哈哈，提前谢谢：