我有这个java代码:多个SQL查询单查询加盟
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();
.
.
.
}
其中getNewMail
是:
public synchronized ArrayList<MessageMap> getNewMail(int UserID,int type,int max){
ArrayList<MessageMap> map = new ArrayList<MessageMap>();
try {
pstmt = conn.prepareStatement("SELECT * FROM MessageMap WHERE UserID = ? AND TipoID = ? AND MessageID > ?");
.
.//fill arraylist with resultSet
.
}
我知道这是有可能做同样的只有一个查询,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
但我取回:
#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
请参阅编辑页:(我有错误 – JackTurky
@JackTurky,对不起,我忘了'ON',看我的编辑。它应该是'INNER JOIN MessageMap p ON i.MessageID = p .MessageID'而不是'INNER JOIN MessageMap p i.MessageID = p.MessageID'。 –
好!!!这是我需要的!谢谢!:) – JackTurky