COALESCE not supported

[avi-beetul]

raise InvalidQueryException(message)
sql_to_ibis.exceptions.sql_exception.InvalidQueryException: Invalid query!
Expected one of the following input(s): {'UNION', 'ORDER', 'LIMIT', 'ON', 'DESC', 'DOT', '__ANON_4', 'WINDOW', 'END', '__ANON_1', 'MINUS', 'RPAR', 'GROUP', 'AND', 'IN', 'EQUAL', 'STAR', 'SLASH', 'WHERE', 'THEN', '__ANON_3', 'NAME', 'HAVING', 'CROSS', 'JOIN', 'ASC', 'EXCEPT', 'LESSTHAN', 'JOIN_TYPE', 'BETWEEN', 'PLUS', 'AS', 'INTERSECT', '__ANON_2', 'COMMA', 'ELSE', 'WHEN', 'OR', 'NOT', 'MORETHAN', 'FROM'}
Unexpected input at line 6, column 29
                    COALESCE(df1.column, df2.column) AS c1

[zbrookle]

@avi-beetul Thanks for pointing that out, I'll add that function