PHP MySQL查詢-添加更多字段時文檔為空

Question

我有這個運行良好的mysql查詢：

$query = "SELECT
          USER.USER_ID, NAME, SURNAME, EMAIL, STATUS, PHOTO
          FROM FRIENDLIST, USER, USER_PROFILE
          WHERE FRIENDLIST.FRIEND_ID = ANY (
              SELECT FRIEND_ID FROM FRIENDLIST WHERE USER_ID=".$userID."
          )
          AND APPROVED='YES'
          AND USER.USER_ID=FRIENDLIST.FRIEND_ID
          AND USER.USER_ID=USER_PROFILE.USER_ID
          UNION
          SELECT
          USER.USER_ID, NAME, SURNAME, EMAIL, STATUS, PHOTO FROM FRIENDLIST, USER, USER_PROFILE
          WHERE FRIENDLIST.FRIEND_ID = " . $userID . "
          AND APPROVED = 'YES'
          AND USER.USER_ID=FRIENDLIST.USER_ID
          AND USER.USER_ID=USER_PROFILE.USER_ID";

當我在查詢中添加更多字段時，出現“文檔為空”錯誤。

$query = "SELECT
          USER.USER_ID, NAME, SURNAME, EMAIL, STATUS, PHOTO, gender, cposition, rinterest, about
          FROM FRIENDLIST, USER, USER_PROFILE
          WHERE FRIENDLIST.FRIEND_ID = ANY (
              SELECT FRIEND_ID FROM FRIENDLIST WHERE USER_ID=" . $userID . "
          )
          AND APPROVED='YES'
          AND USER.USER_ID=FRIENDLIST.FRIEND_ID
          AND USER.USER_ID=USER_PROFILE.USER_ID
          UNION
          SELECT
          USER.USER_ID, NAME, SURNAME, EMAIL, STATUS, PHOTO
          FROM FRIENDLIST, USER, USER_PROFILE
          WHERE FRIENDLIST.FRIEND_ID = ".$userID."
          AND APPROVED='YES'
          AND USER.USER_ID=FRIENDLIST.USER_ID
          AND USER.USER_ID=USER_PROFILE.USER_ID";

新字段屬於USER_PROFILE表。

Answer 1

您使用的是UNION因此兩個SELECT查詢必須具有完全相同的列數。 否則，您的查詢將失敗，並且可能會產生類似於您看到的錯誤。 該錯誤消息還可能表明未檢查查詢結果是否有錯誤或失敗。

如果代碼格式正確，這將更容易發現。 允許（建議）在SQL查詢中使用Enter。