public double sumMoney(int orderid){
double totalmoney=0;
Connection conn=this.getConn();
String sql="select sum(totalmoney) as total from orderdetail where orderid=?";
try {
ps=conn.prepareStatement(sql);
ps.setInt(1, orderid);
totalmoney=ps.get
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return totalmoney;
}
如何获取聚合函数total的值
ResultSet rs = ps.executeQuery();
if(rs.next()){
totalmoney=ps.getDouble("total");
}
如下写法
public double sumMoney(int orderid){ double totalmoney=0; Connection conn=this.getConn(); String sql="select sum(totalmoney) as total from orderdetail where orderid=?"; try { ps=conn.prepareStatement(sql); ps.setInt(1, orderid); ResultSet res = pstmt.executeQuery(); if(res.next()){ double temp=Double.parseDouble(res.getObject(1).toString()) } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return totalmoney; }
otalmoney=ps.getdouble(total);
或者otalmoney=ps.getdouble(第几列);