Question

我正在尝试在我的函数中执行以下操作，但是我收到了一个错误 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 COUNT(1) FROM users WHERE registered_at BETWEEN '1293861600' AND '1303' at line 1")

我基本上试图将第一个SELECT语句与第二个SELECT语句分开。

cursor.execute( "(SELECT COUNT(1) FROM users WHERE "
                    "       (registered_at BETWEEN '1293861600' AND '1303729537') "
                    "                   AND user_id IN (    SELECT parent_id FROM files "
                    "                                       WHERE created_at > '1293861600')) / "
                    "(SELECT COUNT(1) FROM users " 
                    "WHERE registered_at BETWEEN '1293861600' AND '1303729537') " )

另外，有没有更好的方法来重写这个查询？

Answer 1

您可能需要在查询前添加SELECT。

Answer 2

cursor.execute( "SELECT COUNT(1) "
                " / ( SELECT COUNT(1) FROM users " 
                "     WHERE registered_at BETWEEN '1293861600' AND '1303729537') " 
                " FROM users "
                " WHERE ( registered_at BETWEEN '1293861600' AND '1303729537') "
                "   AND user_id IN ( SELECT parent_id FROM files "
                "                    WHERE created_at > '1293861600') " )

IN 可以更改为加入：

cursor.execute( " SELECT COUNT(DISTINCT users.user_id) "
                "        / ( SELECT COUNT(1) FROM users " 
                "            WHERE registered_at "
                "              BETWEEN '1293861600' AND '1303729537') " 
                " FROM users "
                "   JOIN files "
                "     ON files.parent_id = users.user_id "
                " WHERE ( users.registered_at BETWEEN '1293861600' AND '1303729537') "
                "   AND ( files.created_at > '1293861600') "
              )

也可以使用一个子查询重写查询，如下所示：

cursor.execute( " SELECT SUM(IF(user_id IN ( SELECT parent_id "
                "                            FROM files "
                "                            WHERE created_at > '1293861600') "
                "              ,1 ,0 ) ) "
                "        / COUNT(1) "
                " FROM users "
                " WHERE users.registered_at BETWEEN '1293861600' AND '1303729537' "
              )

Answer 3

你需要在整个事情之前进行选择，因此：

cursor.execute( "select (SELECT COUNT(1) FROM users WHERE " ...

Answer 4

执行以下查询以查看您想要的内容..

SELECT（SELECT COUNT（1）FROM users WHERE registered_at BETWEEN 1293861600 AND 1303729537 AND user_id IN（SELECT parent_id FROM files WHERE created_at＆gt; 1293861600））/（SELECT COUNT（1）FROM users WHERE registered_at BETWEEN 1293861600 AND 1303729537）As结果

只有在两个select语句中只得到一个结果时，上述除法才有效。

这个查询出了什么问题？

4 个答案: