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我在phpMyAdmin中測試了我的sql查詢並且它在那裏工作。但是當我複製它並粘貼到我的代碼中時，它會返回NULL。我的其他代碼是無錯誤的，因爲當我刪除這個SQL查詢時它工作的很好。因此，我相信這個查詢存在一些問題。我花了2天找到問題。重要的是it works if I remove INNER JOIN。我嘗試使用JOIN和FULL JOIN，但沒有一個能夠工作。有沒有人看到這個查詢有任何問題？「Multiple SELECT，INNER JOIN」sql查詢不起作用
下面是我的查詢：
SELECT *
From (
SELECT userTrip.id,userTrip.fromLat,userTrip.fromLon,userTrip.toLat,userTrip.toLon
From userTrip
WHERE userTrip.userId != :userId
AND userTrip.departureTime > CURDATE()
AND ABS(UNIX_TIMESTAMP(userTrip.departureTime) - UNIX_TIMESTAMP(:departureTime)) <= " . DEPARTURETIME_DIFFERENCE_THRESHOLD . " * 60
AND userTrip.fromLat Between :fromMinLat AND :fromMaxLat
AND userTrip.fromLon Between :fromMinLon AND :fromMaxLon
) AS SourcesNearBy FULL JOIN user ON user.id = SourcesNearBy.userId ORDER BY user.id
WHERE toLat Between :toMinLat AND :toMaxLat
AND toLon Between :toMinLon AND :toMaxLon
AND (user.gender LIKE :matchGender OR :matchGender LIKE 'A')
AND (:matchAge = -1 OR (CAST(DATEDIFF(CURDATE(),user.birthdate)/365.25 AS UNSIGNED) Between (:matchAge - " . MAX_AGE_DIFFERENCE . ") AND (:matchAge + " . MAX_AGE_DIFFERENCE . ")))
謝謝。
這是我的代碼：
public function findMatchesForUser($userId,$tripId)
{
$sql = "SELECT * from userTrip WHERE tripFinished = 0 AND id = :tripId";
$stmt = $this->dbLink->prepare($sql);
$stmt->bindParam(':tripId', $tripId, PDO::PARAM_INT);
try
{
$stmt->execute();
$userTrip = $stmt->fetchObject();
}
catch (PDOException $err)
{
echo $err->getMessage();
}
if ($userTrip == null)
throw new Frapi_Error('Error Code : 500. Try again.');
// get user's trip length
$distanceClass = new Distance();
$userTripLength = $distanceClass->drivingDistance($userTrip->fromLat, $userTrip->fromLon, $userTrip->toLat, $userTrip->toLon);
// set up first bounding square
$this->setUpBoundingSquare($userTrip->fromLat, $userTrip->fromLon, $userTripLength * SOURCE_DISTANCE_THRESHOLD/100, 1);
// set up bounding second square
$this->setUpBoundingSquare($userTrip->toLat, $userTrip->toLon, $userTripLength * DESTINATION_DISTANCE_THRESHOLD/100, 0);
// perform first phase of algorithm
$Candidates = $this->firstPhase($userId,$userTrip);
}
private function firstPhase($userId,$userTrip)
{
$sql = "SELECT *
From (
SELECT userTrip.id,userTrip.fromLat,userTrip.fromLon,userTrip.toLat,userTrip.toLon
From userTrip INNER JOIN user ON userTrip.userId = user.id
WHERE userTrip.userId != :userId
AND (user.gender LIKE :matchGender OR :matchGender LIKE 'A')
AND (:matchAge = -1 OR (CAST(DATEDIFF(CURDATE(),user.birthdate)/365.25 AS UNSIGNED) Between (:matchAge - " . MAX_AGE_DIFFERENCE . ") AND (:matchAge + " . MAX_AGE_DIFFERENCE . ")))
AND userTrip.departureTime > '".date('Y-m-d H:i:s')."'
AND ABS(UNIX_TIMESTAMP(userTrip.departureTime) - UNIX_TIMESTAMP(:departureTime)) <= " . DEPARTURETIME_DIFFERENCE_THRESHOLD . " * 60
AND userTrip.fromLat Between :fromMinLat AND :fromMaxLat
AND userTrip.fromLon Between :fromMinLon AND :fromMaxLon
) AS SourcesNearBy
WHERE toLat Between :toMinLat AND :toMaxLat
AND toLon Between :toMinLon AND :toMaxLon;";
$stmt = $this->dbLink->prepare($sql);
// Bind parameters
$stmt->bindParam(':fromMinLat', $this->fromMinLat, PDO::PARAM_STR);
$stmt->bindParam(':fromMinLon', $this->fromMinLon, PDO::PARAM_STR);
$stmt->bindParam(':fromMaxLat', $this->fromMaxLat, PDO::PARAM_STR);
$stmt->bindParam(':fromMaxLon', $this->fromMaxLon, PDO::PARAM_STR);
$stmt->bindParam(':toMinLat', $this->toMinLat, PDO::PARAM_STR);
$stmt->bindParam(':toMinLon', $this->toMinLon, PDO::PARAM_STR);
$stmt->bindParam(':toMaxLat', $this->toMaxLat, PDO::PARAM_STR);
$stmt->bindParam(':toMaxLon', $this->toMaxLon, PDO::PARAM_STR);
$stmt->bindParam(':userId', $userId, PDO::PARAM_INT);
$stmt->bindParam(':matchGender', $userTrip->matchGender, PDO::PARAM_STR);
$stmt->bindParam(':matchAge', $userTrip->matchAge, PDO::PARAM_INT);
$stmt->bindParam(':departureTime', $userTrip->departureTime, PDO::PARAM_STR);
try
{
$stmt->execute();
$Candidates = $stmt->fetchAll();
}
catch (PDOException $err)
{
echo $err->getMessage();
}
// If no matchCandidates
if ($Candidates == null)
throw new Frapi_Error("No match candidates found!");
return $Candidates;
}
它運行完美的備用查詢。但它的表現並不好。我想在外部SELECT中移動INNER JOIN。
$sql = "SELECT *
From (
SELECT userTrip.id,userTrip.fromLat,userTrip.fromLon,userTrip.toLat,userTrip.toLon
From userTrip INNER JOIN user ON userTrip.userId = user.id
WHERE userTrip.userId != :userId
AND (user.gender LIKE :matchGender OR :matchGender LIKE 'A')
AND (:matchAge = -1 OR (CAST(DATEDIFF(CURDATE(),user.birthdate)/365.25 AS UNSIGNED) Between (:matchAge - " . MAX_AGE_DIFFERENCE . ") AND (:matchAge + " . MAX_AGE_DIFFERENCE . ")))
AND userTrip.departureTime > '".date('Y-m-d H:i:s')."'
AND ABS(UNIX_TIMESTAMP(userTrip.departureTime) - UNIX_TIMESTAMP(:departureTime)) <= " . DEPARTURETIME_DIFFERENCE_THRESHOLD . " * 60
AND userTrip.fromLat Between :fromMinLat AND :fromMaxLat
AND userTrip.fromLon Between :fromMinLon AND :fromMaxLon
) AS SourcesNearBy
WHERE toLat Between :toMinLat AND :toMaxLat
AND toLon Between :toMinLon AND :toMaxLon;";
查詢通過去除FULL JOIN
SELECT *
From (
SELECT userTrip.id,userTrip.fromLat,userTrip.fromLon,userTrip.toLat,userTrip.toLon
From userTrip
WHERE userTrip.userId != :userId
AND userTrip.departureTime > CURDATE()
AND ABS(UNIX_TIMESTAMP(userTrip.departureTime) - UNIX_TIMESTAMP(:departureTime)) <= " . DEPARTURETIME_DIFFERENCE_THRESHOLD . " * 60
AND userTrip.fromLat Between :fromMinLat AND :fromMaxLat
AND userTrip.fromLon Between :fromMinLon AND :fromMaxLon
) AS SourcesNearBy INNER JOIN user ON user.id = SourcesNearBy.userId
WHERE toLat Between :toMinLat AND :toMaxLat
AND toLon Between :toMinLon AND :toMaxLon
AND (user.gender LIKE :matchGender OR :matchGender LIKE 'A')
AND (:matchAge = -1 OR (CAST(DATEDIFF(CURDATE(),user.birthdate)/365.25 AS UNSIGNED) Between (:matchAge - " . MAX_AGE_DIFFERENCE . ") AND (:matchAge + " . MAX_AGE_DIFFERENCE . ")))
userTrip表
id | userName<br>
1 | A<br>
2 | B<br>
3 | C<br>
4 | D<br>
5 | E<br>
6 | F<br>
表用戶
id | userId | fromLat | fromLon | toLat | toLon | departureTime | matchGender | matchAge<br>
5 | 1 | 40.712898 | -74.013199 | 40.728157 | -74.077644 | 2013-04-26 15:56:08 | M | 25<br>
10 | 2 | 28.520140 | -81.388771 | 28.054642 | -82.469940 | 2013-01-17 10:34:56 | F | 30<br>
檢查你的mysql日誌，看看你的最終請求。 –