【问题标题】:What's wrong with my SQL-EXCEPT-Operator?我的 SQL-EXCEPT-Operator 出了什么问题?
【发布时间】:2018-02-01 16:17:40
【问题描述】:

当我从我的表格“Stats”和“Book”中选择“BookID”时,我会分别得到想要的结果:

MariaDB [db1]> SELECT BookID From Book WHERE Author = 'AuthorX';
+--------+
| BookID |
+--------+
|   1003 |
+--------+


MariaDB [db1]> SELECT BookID From Stats WHERE BookID >= 1000;
+--------+
| BookID |
+--------+
|   1010 |
|   1005 |
|   1003 |
+--------+

但是当我尝试使用 EXCEPT 运算符时,我得到一个错误

MariaDB [db1]> (SELECT BookID From Stats WHERE BookID >= 1000)
     -> EXCEPT
     -> (SELECT BookID From Book WHERE Author = 'AuthorX');
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'EXCEPT (SELECT BookID From Book WHERE Author = 'AuthorX')' at line 1

我希望的输出:

+--------+
| BookID |
+--------+
|   1010 |
|   1005 |
+--------+

我做错了什么? 我试过带括号和不带括号,但不知道下一步该尝试什么?

编辑:尝试使用 NOT IN

SELECT BookID From Stats WHERE BookID >= 1000 NOT IN  
(SELECT BookID From Book WHERE Author = 'AuthorX');

产量

+--------+
| BookID |
+--------+
|      3 |
|   1010 |
|   1005 |
|   1003 |
+--------+

EDIT2:“AND BookID NOT IN”(除作品外)

仍然很想知道为什么 EXCEPT 没有

EDIT3https://mariadb.com/kb/en/library/except/ 中的示例确实有效……

EDIT4:MariaDB Vers似乎是是答案。

仍然想知道为什么这些示例有效......

【问题讨论】:

  • 在@MatBaillie 发布的链接中,它说except 是在10.3.0 中引入的。你用的是什么版本?
  • @kai-dj 我很惊讶你的NOT IN () 竟然被执行了。应该是AND BookID NOT IN ()
  • @kai-dj - 将AND BookID 放在它应该在的位置,看看是否可以修复它,目前我什至不知道这意味着什么,更不用说它为什么会执行。 (祝你好运,我今天不在家……)
  • EXCEPT was introduced in MariaDB 10.3.0.。这是否回答了仍然很想知道为什么 EXCEPT 没有部分?
  • @MatBailie 哦耶-抱歉我的头开始受伤了^^

标签: sql mysql-error-1064 sql-except


【解决方案1】:

去掉括号。

三行看起来“更好”...

SELECT `BookID` From `Stats` WHERE `BookID` >= 1000
EXCEPT
SELECT `BookID` From `Book`  WHERE `Author`  = 'AuthorX'

这和你在UNION ALL看到的差不多...

SELECT BookID From Book WHERE Title LIKE 'Harry Potter%'
UNION ALL
SELECT BookID From Book WHERE Author LIKE '%Toklien%'


编辑

或者只是尝试另一种表达方式(如果在旧版本的 MariaDB 上)...

SELECT BookID
  FROM Book
 WHERE BookID >= 1000
   AND BookID NOT IN (SELECT BookID
                        FROM Book
                       WHERE Author = 'AuthorX'
                     )

或者……

SELECT BookID
  FROM Book
 WHERE BookID >= 1000
   AND NOT EXISTS (SELECT *
                     FROM Book  lookup
                    WHERE lookup.Author = 'AuthorX'
                      AND lookup.BookID = Book.BookID
                  )

或者……

SELECT
  *
FROM
(
  SELECT BookID FROM Book WHERE BookID >= 1000
)
  high_id
LEFT JOIN
(
  SELECT BookID FROM Book WHERE Author = 'AuthorX'
)
  target_author
    ON target_author.BookID = high_id.BookID
WHERE
  target_author.BookID IS NULL

【讨论】:

  • 那么你在某处的另一行还有其他问题...mariadb.com/kb/en/library/except (尝试自行运行;,然后在最后使用; 再次尝试查询。)
  • 这是唯一的一行……
  • 你试过了吗? (以防万一有其他东西不小心...)
  • 两者都做了——结果相同
  • 只运行前半部分会得到什么(除此之外)
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