base64 function
Applies to: 
Databricks SQL Databricks Runtime
Converts expr to a base 64 string using RFC2045 Base64 transfer encoding for MIME.
Syntax
base64(expr)
Arguments
expr: A BINARY expression or a STRING which the function will interpret as BINARY.
Returns
A STRING.
Examples
> SELECT base64('Spark SQL');
U3BhcmsgU1FM