Applies to: 
Databricks SQL Databricks Runtime
Returns -1.0, 0.0, or 1.0 as expr is negative, 0, or positive. This function is a synonym for signum function.
Syntax
sign(expr)
Arguments
expr: An expression that evaluates to a numeric or interval.
Interval is supported since: Databricks Runtime 10.1)
Returns
A DOUBLE.
Examples
> SELECT sign(40);
1.0
> SELECT sign(INTERVAL'-1' DAY)
-1.0