Share via

LIMIT 子句

  • 發行項

適用于：核取標示為是 Databricks SQL 檢查標示為是 Databricks Runtime

限制 查詢所傳回的資料列數目。 一般而言，這個子句會與 ORDER BY 搭配使用，以確保結果具決定性。

語法

LIMIT { ALL | integer_expression }

參數

  • 所有

    如果指定，查詢會傳回所有資料列。 換句話說，如果未指定此選項，則不會套用任何限制。

  • integer_expression

    傳回整數的常值運算式。

例子

> 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