to_unix_timestamp function
Applies to: 
Databricks SQL Databricks Runtime
Returns the timestamp in expr as a UNIX timestamp.
Syntax
to_unix_timestamp(expr [, fmt] )
Arguments
expr: A STRING expression representing a timestamp.- fmt: An optional format STRING expression.
Returns
A BIGINT.
If fmt is supplied, it must conform with Datetime patterns.
If fmt is not supplied, the function is a synonym for cast(expr AS TIMESTAMP).
If fmt is malformed or its application does not result in a well formed timestamp, the function raises an error.
Note
In Databricks Runtime, if spark.sql.ansi.enabled is false, the function returns NULL instead of an error for malformed timestamps.
Examples
> SELECT to_unix_timestamp('2016-04-08', 'yyyy-MM-dd');
1460098800