FORALL

Description

The FORALL function is used to determine whether all elements in an array meet a specified condition. This function takes an array and a single-parameter lambda expression as input and returns a boolean result.

Syntax

FORALL(array, x -> expr)

Parameter Description

• array: The input array, of type array<T>.
• x -> expr: A single-parameter lambda expression, where x corresponds to an element in the array, and expr is an expression that needs to return a boolean value.

Return Result

• Returns a boolean value indicating whether all elements in the array satisfy the condition specified by the lambda expression.

Example

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

   SELECT FORALL(array(1, 2, 3, 4, 5), x -> x <= 3) AS result;
   

Result:

result
-------
false

2. Determine if all elements in the array are greater than 10:

   SELECT FORALL(array(1, 20, 30, 4), x -> x > 10) AS result;
   

Result:

result
-------
false

3. Determine if all non-null elements in an array containing null values are less than or equal to 3:

   SELECT FORALL(array(1, null, 3), x -> IF(x IS NOT NULL, x <= 3, true)) AS result;
   

Result:

result
-------
true

4. Determine if all even elements in the array are greater than or equal to 2:

   SELECT FORALL(array(1, 2, 3, 4, 6), x -> MOD(x, 2) = 0 AND x >= 2) AS result;
   

Result:

result
-------
false

Notes

• When the array is empty, the FORALL function will return a NULL value.
• When the condition in the lambda expression is not satisfied by all elements, the function returns false.
• When the condition in the lambda expression is satisfied by all elements, the function returns true.