array_null() -> generic array

Returns a null value of type array.

This is important because some functions, like case(), return more convenient outputs if all their arguments are of the same type.

Domain

This is a scalar function (calculates a single output value for a single input row).

Categories

• Semistructured

Examples

make_col positive_or_null:case(x > 0, x, true, array_null())

Create a column 'positive_or_null' which is either a positive array, or the null array.