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首页 > 解决方案 > 2 查询单独运行良好，但组合起来会产生语法错误

mysql - 2 查询单独运行良好，但组合起来会产生语法错误

问题描述

第一个查询与与特定主题相关的书籍和作者列表相关，并产生正确的结果：

SELECT BOOK_NUM,
BOOK_TITLE,
BOOK_SUBJECT,
AU_LNAME
FROM BOOK
JOIN WRITES USING (BOOK_NUM)
JOIN AUTHOR USING (AU_ID)
WHERE BOOK_SUBJECT = 'CLOUD'
ORDER BY BOOK_TITLE;

第二个扩展了主题并产生了正确的结果：

SELECT BOOK_NUM,
BOOK_TITLE,
BOOK_SUBJECT,
AU_FNAME,
AU_LNAME,
Count(BOOK_TITLE) AS `NUM BOOKS BY AUTHOR`
FROM BOOK
JOIN WRITES USING (BOOK_NUM)
JOIN AUTHOR USING (AU_ID)
GROUP BY BOOK_NUM, AU_ID
ORDER BY `NUM BOOKS BY AUTHOR`,
AU_LNAME;

当我将两者结合起来时，它会在 WHERE BOOK_SUBJECT = 'CLOUD' 处产生语法错误：

SELECT BOOK_NUM,
BOOK_TITLE,
BOOK_SUBJECT,
AU_FNAME,
AU_LNAME,
Count(BOOK_TITLE) AS `NUM BOOKS BY AUTHOR`
FROM BOOK
JOIN WRITES USING (BOOK_NUM)
JOIN AUTHOR USING (AU_ID)
GROUP BY BOOK_NUM, AU_ID
WHERE BOOK_SUBJECT = 'CLOUD'
ORDER BY `NUM BOOKS BY AUTHOR`, 
AU_LNAME,
BOOK_TITLE;

无论我把它放在哪里，我都会得到同样的错误，如果我删除它，代码就会运行。我需要做什么来解决这个问题？我需要包含这个 where 子句。预先感谢您帮助我。

标签： mysqlwhere

解决方案

不确定您使用的是什么 SQL。尝试将 WHERE 子句移到 GROUP BY 之上。

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