php - 带有左联接的MySQL查询-如果两行相同则专门索引

我的数据库中有一个名为users的表，另一个名为grouppost的表。这两个表的共同点是id行。因此，当我进行一个将两个表连接在一起的sql查询时，如何确定想要的id行？
例

$sql = "SELECT gp.*, u.*
      FROM grouppost
      AS gp LEFT JOIN users AS u ON u.username = gp.author
      WHERE gp.gname = ? AND gp.type = ? ORDER BY gp.pdate DESC $limit";
      $stmt = $conn->prepare($sql);
      $stmt->bind_param("ss",$g,$zero);
      $stmt->execute();
      $result_new = $stmt->get_result();
      if ($result_new->num_rows > 0){
         while ($row = $result_new->fetch_assoc()) {
            $grouppost_id = $row["id"]; // I want to get the id from table grouppost but I get the id from the users table
         }
      }

最佳答案

如果要在结果集中将其单独定位，则可以在选择的内容中为其添加别名：

SELECT gp.*, u.*, gp.id AS grouppost_id
FROM grouppost AS gp
LEFT JOIN users AS u ON u.username = gp.author
WHERE gp.gname = ?
  AND gp.type = ?
ORDER BY gp.pdate DESC
$limit

关于php - 带有左联接的MySQL查询-如果两行相同则专门索引，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/47955497/