avg函数的简单使用(求平均成绩)

2015-04-06 10:12:55 访问(1694) 赞(0) 踩(0)

生成和输出的SQL语句

select avg(Score) from UTB_EXAM_SCORE t

关键代码

entity.avgEntityFieldInfo = entity._Score;

代码写法

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using SlowX.DAL.Helpers;
using SlowX.Core.ICoreClasses;
using System.Data;
using SlowX.Functions.Functions;
using SlowX.Core.CoreClasses;

public partial class ExamSQL : System.Web.UI.Page
{
    protected string strResult = "";

    protected void Page_Load(object sender, EventArgs e)
    {
        DataBindTheContorls(null);
    }

    #region 操作

    /// <summary>
    /// 
    /// </summary>
    /// <param name="xdbHelper"></param>
    protected void DataBindTheContorls(DBHelper xdbHelper)
    {
        string theResult = null;
        bool bIsCreate = true;

        if (xdbHelper == null)
        {
            xdbHelper = SlowX.DAL.Helpers.DBHelper.CreateDBHelper();
        }
        else
        {
            // 没有打开链接 //
            bIsCreate = xdbHelper.IsNotOpen();
        }

        try
        {
            if (bIsCreate)
                xdbHelper.OpenDBHelper();

            // 获得数据库操作的实体 //
            SlowX.ExamLib.Business.UTB_EXAM_SCORE
                bll
                =
                SlowX.ExamLib.Business.UTB_EXAM_SCORE.instance;

            // 创建SQL操作的载体 //
            SlowX.ExamLib.Entity.UTB_EXAM_SCORE
                entity
                =
                new SlowX.ExamLib.Entity.UTB_EXAM_SCORE();


            entity.avgEntityFieldInfo = entity._Score;

            object oValue = bll.Avg(entity, xdbHelper);

            theResult =
                @"<textarea name=""TextBox1"" rows=""2"" cols=""20"" id=""TextBox1"" style=""height:400px;width:99%;"">"
                + bll.BuildSqlAvg(entity, xdbHelper)
                + "</textarea>";

            theResult += "<br /><br />";

            theResult += StringSlowXFunctions.ObjToString(oValue, "");

            if (bIsCreate)
                xdbHelper.EndDBHelper();

        }
        catch (Exception err)
        {
            if (bIsCreate)
                xdbHelper.TranDBHelper();

            throw err;
        }
        finally
        {
            if (bIsCreate)
                xdbHelper.FinallyDBHelper();
        }

        strResult = theResult;
    }

    #endregion 操作

}