在 PHP PDO 中如何获取 PostgreSQL upsert 查询的“RETURNING”子句值

我用 postgreSQL 编写了这个 upsert 查询

$statement = 'INSERT INTO "CharactersUnlockToBuyLevels"
                ("CharacterId", "LevelId", "AmountToBuy", "EagleStatueId", "Location", 
                 "MapCoordinateTop", "MapCoordinateLeft")
              VALUES 
                (:CharacterId, :LevelId, :AmountToBuy, :EagleStatueId, :Location, 
                 :MapCoordinateTop, :MapCoordinateLeft)
              ON CONFLICT
                ("CharacterId")
              DO UPDATE 
                SET 
                  "LevelId" = EXCLUDED."LevelId",
                  "AmountToBuy" = EXCLUDED."AmountToBuy",
                  "EagleStatueId" = EXCLUDED."EagleStatueId",
                  "Location" = EXCLUDED."Location",
                  "MapCoordinateTop" = EXCLUDED."MapCoordinateTop",
                  "MapCoordinateLeft" = EXCLUDED."MapCoordinateLeft"                            
              RETURNING "CharacterUnlockToBuyLevelId"
             ';

该查询工作正常，如果我在 PgAdmin 中运行它，我会按预期返回“CharacterUnlockToBuyLevelId”。但是，如果我准备它并使用 PHP 的 PDO 执行它，那么我似乎无法取回返回值。

$stmt = $this->db->prepare($statement);
$returnedId = $stmt->execute(array(
     'CharacterId' => $characterId,
     'LevelId' => $unlockMethod['LevelId'],
     'AmountToBuy' => $unlockMethod['AmountToBuy'],
     'EagleStatueId' => $unlockMethod['EagleStatueId'],
     'Location' => $unlockMethod['Location'],
     'MapCoordinateTop' => $unlockMethod['MapCoordinateTop'],
     'MapCoordinateLeft' => $unlockMethod['MapCoordinateLeft'],
));

这只是返回 true，所以$returnedId实际上不会保存 id，而只是保存 true 值。如何使用 PDO 的准备语句从 upsert 查询中获取 RETURNING 值？

from http://php.net/manual/en/pdostatement.execute.php:

公共 bool PDOStatement::execute ([ 数组 $input_parameters ] )

要获得返回的 val，请尝试fetchAll

$stmt = $this->db->prepare($statement);
$returnedId = $stmt->execute(array(
     'CharacterId' => $characterId,
     'LevelId' => $unlockMethod['LevelId'],
     'AmountToBuy' => $unlockMethod['AmountToBuy'],
     'EagleStatueId' => $unlockMethod['EagleStatueId'],
     'Location' => $unlockMethod['Location'],
     'MapCoordinateTop' => $unlockMethod['MapCoordinateTop'],
     'MapCoordinateLeft' => $unlockMethod['MapCoordinateLeft'],
));
$yourVal=$stmt->fetchAll();