nvl function
Applies to: 
Databricks SQL Databricks Runtime
Returns expr2 if expr1 is NULL, or expr1 otherwise. This function is a synonym for coalesce(expr1, expr2) with two arguments.
Syntax
nvl(expr1, expr2)
Arguments
expr1: An expression of any type.expr2: An expression that shares a least common type withexpr1.
Returns
The result type is the least common type of the argument types.
Special considerations apply to VARIANT types. See isnull function for details.
Examples
SQL
> SELECT nvl(NULL, 2);
2
> SELECT nvl(3, 2);
3