[英]How to get the return with executeQuery() in Java?
我有这个代码;
String sql = "UPDATE Players SET Losses=Losses+1 WHERE UUID='" + p.getUniqueId() + "';";
stmt.executeUpdate(sql);
如何获得特定Player p
的当前Losses
?
SELECT查询将返回它,但是您真正的问题是什么?
字符串sql =“ SELECT column_name,column_name FROM table_name WHERE column_name =”“;”;
我将使用Select for Update,这样的东西-
String query = "SELECT Losses FROM Players FOR UPDATE "
+ "Players SET Losses=Losses+1 WHERE UUID=?";
ps = conn.prepareStatement(query,
ResultSet.TYPE_FORWARD_ONLY,
ResultSet.CONCUR_UPDATABLE);
ps.setString(1, p.getUniqueId());
ResultSet rs = ps.executeQuery();
int losses = 0;
if (rs.next()) {
losses = rs.getInt("Losses");
}
您可以得到如下损失。 似乎真的很琐碎,猜你是绝对的初学者。
String sql = "SELECT Losses FROM Players WHERE UUID='" + p.getUniqueId() + "';";
ResultSet rs = stmt.executeQuery(sql);
int losses = -1;
if(rs.next()) {
losses = rs.getInt("Losses");
}
您将必须执行SELECT语句。 就像SELECT会从玩家那里丢失UUID ='“ + p.getUniqueId()+”';“;然后使用Statement的executeQuery()返回一个ResultSet。您可以使用迭代器从ResultSet对象中提取数据。
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