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://www.amazonaws.cn/blogs/big-data/amazon-redshift-python-user-defined-functions-will-reach-end-of-support-after-june-30-2026/)。

# SELECT
<a name="r_SELECT_synopsis"></a>

返回表、视图和用户定义的函数中的行。

**注意**  
单个 SQL 语句的最大大小为 16MB。

## 语法
<a name="r_SELECT_synopsis-synopsis"></a>

```
[ WITH with_subquery [, ...] ]
SELECT
[ TOP number | [ ALL | DISTINCT ]
* | expression [ AS output_name ] [, ...] ]
[ EXCLUDE column_list ]
[ FROM table_reference [, ...] ]
[ WHERE condition ]
[ [ START WITH expression ] CONNECT BY expression ]
[ GROUP BY ALL | expression [, ...] ]
[ HAVING condition ]
[ QUALIFY condition ]
[ { UNION | ALL | INTERSECT | EXCEPT | MINUS } query ]
[ ORDER BY expression [ ASC | DESC ] ]
[ LIMIT { number | ALL } ]
[ OFFSET start ]
```

**Topics**
+ [语法](#r_SELECT_synopsis-synopsis)
+ [WITH 子句](r_WITH_clause.md)
+ [SELECT 列表](r_SELECT_list.md)
+ [EXCLUDE column\$1list](r_EXCLUDE_list.md)
+ [FROM 子句](r_FROM_clause30.md)
+ [WHERE 子句](r_WHERE_clause.md)
+ [GROUP BY 子句](r_GROUP_BY_clause.md)
+ [HAVING 子句](r_HAVING_clause.md)
+ [QUALIFY 子句](r_QUALIFY_clause.md)
+ [UNION、INTERSECT 和 EXCEPT](r_UNION.md)
+ [ORDER BY 子句](r_ORDER_BY_clause.md)
+ [CONNECT BY 子句](r_CONNECT_BY_clause.md)
+ [子查询示例](r_Subquery_examples.md)
+ [关联的子查询](r_correlated_subqueries.md)