EXISTS

Description

The EXISTS function is used to determine whether there is an element in the specified array that meets the given condition. By passing in a lambda expression, each element in the array can be evaluated. If at least one element meets the condition, the function returns true; otherwise, it returns false.

Parameters

• array: array<T> type, representing the array to be evaluated.
• x -> expr: A single-parameter lambda expression, where x corresponds to an element in the array; expr needs to return a boolean type, representing the condition to be evaluated.

Return Type

Returns a boolean value.

Example Usage

1. Determine if there is an element in the array that is less than or equal to 3:

SELECT EXISTS(array(1, null, 3), x -> x <= 3);

Results:

true

2. Determine if there are elements in the array that are less than or equal to 0:

SELECT EXISTS(array(1, null, 3), x -> x <= 0);

Result: Returns an empty string

3. Determine if all elements in the array are less than or equal to 0:

SELECT EXISTS(array(1, 3), x -> x <= 0);

Results:

false

4. Determine if there is at least one null value in the array:

SELECT EXISTS(array(1, null, 3), x -> x IS NULL);

Results:

true

5. Determine if there are even numbers in the array:

SELECT EXISTS(array(1, 2, 3, 4), x -> x % 2 = 0);

Results:

true

6. Determine if there are negative numbers in the array:

SELECT EXISTS(array(1, 2, 3, 4), x -> x < 0);

Results:

false