Java 使用内部联接将多个sql查询转换为单个查询

我有以下java代码：

ArrayList<MessageMap> ids = getNewMail(UserID, type, maxIdMessage);
Message[] message = new Message[ids.size()];
if(ids.size()>0){
   ResultSet rs;
   int j =0;
   for(MappaMessaggi i : ids){
      pstmt = conn.prepareStatement("SELECT * FROM Messaggi WHERE MessageID = ?");
      pstmt.setInt(1, i.getMessageID());
      rs = pstmt.executeQuery();
      rs.next();
      .
      .
      .
   }

我知道只需一个查询就可以做到这一点，但我不知道如何。。有人能睁开我的眼睛吗？：）谢谢

编辑：我尝试：

SELECT i.*
FROM Messaggi AS i
INNER JOIN MessageMap AS p i.MessageID = p.MessageID
WHERE p.MessageID = 1 AND p.UserID = 1 AND p.TipoID = 2

但我发现：

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'i.MessageID = p.MessageID WHERE p.MessageID = 1 AND p.UserID = 1 AND p.TipoID = ' at line 3

---

根据您的问题和查询，我找到的简单解决方案可能是此查询（可能还有其他列与您的表相关）

另外，请指定您是否需要这3个参数，或者无法发送任何参数。

请尝试以下操作：

SELECT i.*, p.*
FROM Messaggi i
INNER JOIN MessageMap p ON i.MessageID = p.MessageID
WHERE i.MessageID = ? AND p.UserID = ? AND p.TipoID = ?

---

老实说，可能只是

Messaggi.

。@JackTurky，对不起，我忘了

，请参阅我的编辑。它应该是i.MessageID=p.MessageID

上的

internal JOIN MessageMap p，而不是
internal JOIN MessageMap p i.MessageID=p.MessageID
。
SELECT A.*
FROM MessageMap A
    INNER JOIN Message B on A.MessageId = B.MessageId
WHERE
    A.UserId = ?
    AND A.TipoID = ?
    AND A.MessageId = ?

SELECT i.*, p.*
FROM Messaggi i
INNER JOIN MessageMap p ON i.MessageID = p.MessageID
WHERE i.MessageID = ? AND p.UserID = ? AND p.TipoID = ?