sqrt function
Applies to: 
Databricks SQL Databricks Runtime
Returns the square root of expr.
Syntax
sqrt(expr)
Arguments
expr: An expression that evaluates to a numeric.
Returns
For DECFLOAT inputs, the result is DECFLOAT with the same precision as expr. For other inputs, the result is a DOUBLE.
If expr is negative the result is NaN.
Examples
SQL
> SELECT sqrt(4);
2.0
> SELECT sqrt(-4);
NaN