+----+--------------+------------------------+-------+---------------+------+---------+------+------+--------------------------+
| id | select_type  | table                  | type  | possible_keys | key  | key_len | ref  | rows | Extra                    |
+----+--------------+------------------------+-------+---------------+------+---------+------+------+--------------------------+
|  1 | PRIMARY      | cdr                    | range | calldate,dst  | dst  | 250     | NULL |   87 | Using where; Using index | 
|  2 | UNION        | cdr                    | range | calldate,dst  | dst  | 250     | NULL |   84 | Using where; Using index | 
|  3 | UNION        | cdr                    | range | calldate,dst  | dst  | 250     | NULL |   70 | Using where; Using index | 
|  4 | UNION        | cdr                    | range | calldate,dst  | dst  | 250     | NULL |   98 | Using where; Using index | 
|  5 | UNION        | cdr                    | range | calldate,dst  | dst  | 250     | NULL |   93 | Using where; Using index | 
|  6 | UNION        | cdr                    | range | calldate,dst  | dst  | 250     | NULL |  103 | Using where; Using index | 
|  7 | UNION        | cdr                    | range | calldate,dst  | dst  | 250     | NULL |   85 | Using where; Using index | 
|  8 | UNION        | cdr                    | range | calldate,dst  | dst  | 250     | NULL |    6 | Using where; Using index | 
| NULL | UNION RESULT | <union1,2,3,4,5,6,7,8> | ALL   | NULL          | NULL | NULL    | NULL | NULL |                          | 
+----+--------------+------------------------+-------+---------------+------+---------+------+------+--------------------------+
9 rows in set (0.00 sec)