string_null() -> string

Returns a null value of type string.

This is valuable 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

• String

Examples

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

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