Mysql 如何在SQL查询中按客户名称组合总成本？

我的尝试如下：

SELECT BookLoan.borrowerName, Book.cost
FROM BookLoan
JOIN Book ON BookLoan.bookTitle = Book.title
JOIN Borrower ON BookLoan.borrowerName = Borrower.name;

我需要按

借用名称

合并总成本，但确实不确定如何合并

按和分组

SELECT BookLoan.borrowerName, SUM(Book.cost) as TotalCost
FROM BookLoan
JOIN Book ON BookLoan.bookTitle = Book.title
JOIN Borrower ON BookLoan.borrowerName = Borrower.name
GROUP BY BookLoan.borrowerName

SELECT BookLoan.borrowerName
, SUM(Book.cost) AS TotalCost
FROM BookLoan 
LEFT JOIN Book 
  ON Book.title = BookLoan.bookTitle
LEFT JOIN Borrower 
  ON Borrower.name = BookLoan.borrowerName
GROUP BY BookLoan.borrowerName
ORDER BY BookLoan.borrowerName;

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MySQL 5.x还是8.x？这在8.x中很容易。这里应该有一个简短的代码描述，以获得长期的好答案。除OP@badcoder11外，其他人也会看到未来的帖子。不客气，请接受我的回答。