LIMIT 子句
适用于: Databricks SQL Databricks Runtime
限制查询返回的行数。 通常,此子句会与 ORDER BY 结合使用,以确保结果是确定的。
语法
LIMIT { ALL | integer_expression }
参数
ALL
如果指定了它,查询将返回所有行。 换句话说,如果指定了此选项,则没有限制。
integer_expression
一个返回整数的文本表达式。
示例
> CREATE TEMP VIEW person (name, age)
AS VALUES ('Zen Hui', 25),
('Anil B' , 18),
('Shone S', 16),
('Mike A' , 25),
('John A' , 18),
('Jack N' , 16);
-- Select the first two rows.
> SELECT name, age FROM person ORDER BY name LIMIT 2;
Anil B 18
Jack N 16
-- Select the 4th and 5th rows by alphabetical order.
> SELECT name, age FROM person ORDER BY name LIMIT 2 OFFSET 3;
Mike A 25
Shone S 16
-- Specifying ALL option on LIMIT returns all the rows.
> SELECT name, age FROM person ORDER BY name LIMIT ALL;
Anil B 18
Jack N 16
John A 18
Mike A 25
Shone S 16
Zen Hui 25
-- A function expression as an input to LIMIT.
> SELECT name, age FROM person ORDER BY name LIMIT length('SPARK');
Anil B 18
Jack N 16
John A 18
Mike A 25
Shone S 16
-- A non-literal expression as an input to LIMIT is not allowed.
SELECT name, age FROM person ORDER BY name LIMIT length(name);
Error: The limit expression must evaluate to a constant value