Question

我的sql是：

select (select count(*) from TblRMember where sex=1) male,
 (select count(*) from TblRMember where sex=2) female,
 (select count(*) from TblRMember where sex=0) unkown

我希望Dapper.Net像这样返回一个Dictinary：

Keys:male,female,nukown
Value:10,30,50

我看到How to map to a Dictionary object from database results using Dapper Dot Net?，但这不起作用！

如何使用ToDictionary或其他方式实现我想要的

var myDictionary = sqlConnection.Query(strSql).ToDictionary(??);

谢谢！

Answer 1

首先将您的查询更改为单一查询：

select case when sex = 1 then 'male'
            when sex = 2 then 'female'
            when sex = 0 then 'unknown'
       end as sex, count(*) as cnt
from TblRMember
group by sex

因为我看到sex是数字，所以你要么必须通过名字（性别名？）选择coumn，要么在你的代码中更改它。之后：

var myDictionary = sqlConnection.Query(strSql)
                    .ToDictionary(x => x.sex.ToString(), x => (int)x.cnt);

Answer 2

package task;

import java.io.IOException;
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/STP")
public class STP extends HttpServlet {
    static {
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        int ID = Integer.parseInt(request.getParameter("ID"));
        System.out.println(ID);
        String Name = request.getParameter("Name");
        String Branch = request.getParameter("Branch");
        long Mobile =Long.valueOf(request.getParameter("Mobile"));
        try {

            Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/vikas", "root", "root");

            CallableStatement cs = con.prepareCall("{call Procedure3(?,?,?,?)}");
            cs.setInt(1, ID);
            cs.setString(2, Name);
            cs.setString(3,Branch);
            cs.setLong(4,Mobile);

            cs.execute();
            int id=cs.getInt(1);
            String name=cs.getString(2);
            String branch=cs.getString(3);
            long mobile=cs.getLong(4);
            request.setAttribute("id",id);
            request.setAttribute("name",name);
            request.setAttribute("branch",branch);
            request.setAttribute("mobile",mobile);
            request.getRequestDispatcher("StoredProcedure.jsp").forward(request, response); 
        System.out.println(id);
        } catch (SQLException e) {
            e.printStackTrace();
        }

    }
}

您可以使用别名和强类型。

别名是关键点，与KeyValuePair类型的键和值的属性匹配。

它在强类型下可以正常运行。

我不喜欢动态类型。在某些情况下会带来灾难。而且，装箱和拆箱都会造成性能损失。

Dapper.net使用查询进入字典

2 个答案: