gistfile1.txt

mysql> desc (SELECT * FROM users WHERE email_pc='1-pc@example.com' AND deleted=0) UNION (SELECT * FROM users WHERE email_mobile='1-pc@example.com' AND deleted=0) \G
*************************** 1. row ***************************
           id: 1
  select_type: PRIMARY
        table: users
         type: const
possible_keys: email_pc
          key: email_pc
      key_len: 264
          ref: const,const
         rows: 1
        Extra:
*************************** 2. row ***************************
           id: 2
  select_type: UNION
        table: NULL
         type: NULL
possible_keys: NULL
          key: NULL
      key_len: NULL
          ref: NULL
         rows: NULL
        Extra: Impossible WHERE noticed after reading const tables
*************************** 3. row ***************************
           id: NULL
  select_type: UNION RESULT
        table: <union1,2>
         type: ALL
possible_keys: NULL
          key: NULL
      key_len: NULL
          ref: NULL
         rows: NULL
        Extra:
3 rows in set (0.00 sec)