If two or more columns of the result have the same field names, the last column will take precedence.
fbsql_fetch_assoc() is equivalent to calling fbsql_fetch_array() with FBSQL_ASSOC for the optional second parameter. It only returns an associative array. This is the way fbsql_fetch_array() originally worked. If you need the numeric indices as well as the associative, use fbsql_fetch_array().