从补丁 198 开始，Amazon Redshift 将不再支持创建新的 Python UDF。现有的 Python UDF 将继续正常运行至 2026 年 6 月 30 日。有关更多信息，请参阅[博客文章](https://aws.amazon.com/blogs/big-data/amazon-redshift-python-user-defined-functions-will-reach-end-of-support-after-june-30-2026/)。

# 示例 EXCEPT 查询
<a name="c_Example_MINUS_query"></a>

TICKIT 数据库中的 CATEGORY 表包含以下 11 行：

```
 catid | catgroup |  catname  |                  catdesc
-------+----------+-----------+--------------------------------------------
   1   | Sports   | MLB       | Major League Baseball
   2   | Sports   | NHL       | National Hockey League
   3   | Sports   | NFL       | National Football League
   4   | Sports   | NBA       | National Basketball Association
   5   | Sports   | MLS       | Major League Soccer
   6   | Shows    | Musicals  | Musical theatre
   7   | Shows    | Plays     | All non-musical theatre
   8   | Shows    | Opera     | All opera and light opera
   9   | Concerts | Pop       | All rock and pop music concerts
  10   | Concerts | Jazz      | All jazz singers and bands
  11   | Concerts | Classical | All symphony, concerto, and choir concerts
(11 rows)
```

假定 CATEGORY\$1STAGE 表（临时表）包含一个额外行：

```
 catid | catgroup |  catname  |                  catdesc
-------+----------+-----------+--------------------------------------------
1 | Sports   | MLB       | Major League Baseball
2 | Sports   | NHL       | National Hockey League
3 | Sports   | NFL       | National Football League
4 | Sports   | NBA       | National Basketball Association
5 | Sports   | MLS       | Major League Soccer
6 | Shows    | Musicals  | Musical theatre
7 | Shows    | Plays     | All non-musical theatre
8 | Shows    | Opera     | All opera and light opera
9 | Concerts | Pop       | All rock and pop music concerts
10 | Concerts | Jazz      | All jazz singers and bands
11 | Concerts | Classical | All symphony, concerto, and choir concerts
12 | Concerts | Comedy    | All stand up comedy performances
(12 rows)
```

返回两个表之间的差异。换而言之，返回 CATEGORY\$1STAGE 表中存在但 CATEGORY 表中不存在的行：

```
select * from category_stage
except
select * from category;

catid | catgroup | catname |             catdesc
-------+----------+---------+----------------------------------
12 | Concerts | Comedy  | All stand up comedy performances
(1 row)
```

以下等效查询使用同义词 MINUS。

```
select * from category_stage
minus
select * from category;

catid | catgroup | catname |             catdesc
-------+----------+---------+----------------------------------
12 | Concerts | Comedy  | All stand up comedy performances
(1 row)
```

如果反转 SELECT 表达式的顺序，则查询不返回任何行。