Question

我有一个包含3个表（member，boat，boatType）的数据库，在下面的方法中，其中两个受到影响。我想要的是列出在会员上注册的所有船只，但是代码存在问题（至少使用SQL，但我怀疑不是全部）。

提前致谢。

boatHandler.php：

public function GetMembersBoats($memberId) {

    $query = "SELECT b.boatId, b.length, bt.type
                  FROM boat AS b
                      INNER JOIN member AS m
                          ON b.memberId = m.memberId
                              WHERE m.memberId = ?
                      INNER JOIN boatType AS bt
                          ON b.boatTypeId = bt.boatTypeId
                      GROUP BY b.boatId";

    $stmt = $this->m_db->Prepare($query);
    $stmt->bind_param('i', $memberId);

    $boats = $this->m_db->GetBoats($stmt);
}

database.php中：

public function GetBoats($stmt) {
    $boats = array(
            0 => array(),
            1 => array(),
            2 => array()
        );

    $stmt->execute();

    $stmt->bind_result($boatId, $length, $type);

    while ($stmt->fetch()) {
        array_push($boats[0], $boatId);
        array_push($boats[1], $length);
        array_push($boats[2], $type);
    }

    $stmt->Close();

    return $boats;
}

受影响的表格：

boat： boatId，boatTypeId，length，memberId
boatType： boatTypeId，键入

Answer 1

必须在表引用后列出WHERE子句。您必须在WHERE m.memberId = ?和FROM之后将JOIN移到表格引用的末尾，如下所示：

SELECT b.boatId, b.length, bt.type
FROM boat AS b
      INNER JOIN member AS m
          ON b.memberId = m.memberId

      INNER JOIN boatType AS bt
          ON b.boatTypeId = bt.boatTypeId
WHERE m.memberId = ?
GROUP BY b.boatId

Answer 2

当你在on子句中时，只需将'where'替换为'and'：

SELECT b.boatId, b.length, bt.type
              FROM boat AS b
                  INNER JOIN member AS m
                      ON b.memberId = m.memberId
                          AND m.memberId = ?
                  INNER JOIN boatType AS bt
                      ON b.boatTypeId = bt.boatTypeId
                  GROUP BY b.boatId

无法获得查询工作

受影响的表格：

2 个答案: