动态查询 及 多条件判断优化方法

CREATE proc  GetQsqAdminLogbyWhere

@where varchar(5000)=''

as  

if(@where = '')

    set @where = '1=1'

exec('select * from (

select forums_Users.UserName,QsqAdminLog.*  from forums_Users,QsqAdminLog

 where forums_Users.UserId=QsqAdminLog.UserId ) a where '+@where)

GO

这里的where可以随时传递不同的条件，很适合条件常变动，组合条件。前台即可非常灵活，三种条件模糊着来查都没问题，灵活多变。

void Bind()

        { 

            //根据时间来查询用户登录日志

            string userName = this.txtKey.Text;

            string begin = beginDateID.Value;

            string end = beginDateID18.Value;

            StringBuilder sb=new StringBuilder(" 1=1 "); 

            if(userName.Length > 0)

            {

                sb.Append(" and [UserName] like '%"+userName+"%'");

            }

            if(begin.Length >0)

            {

                sb.Append(" and LoginTime>'"+begin+"' ");

            }

            if(end.Length>0)

            {

                sb.Append("and LoginTime<'"+end+"'");

            }          

    Dg.DataSource = dp.GetQsqAdminLogbyWhere(sb.ToString()).Items;

            Dg.DataBind();           

        }

多种情况下优化if else 条件查询

private void Button1_Click(object sender, System.EventArgs e)

        {

            string begin = beginDateID.Value;

            string end = beginDateID18.Value;

            string name = Utils.inject(txtName.Text);

            //理财帖子数

            DataTable dt1 = dp.SelectSubjectPager(1,1000000000,"","suCreateDate",1,out count,0);

            DataView dv1 = dt1.DefaultView;

            DataTable dt2 = dp.SelectSubjectPager(1,1000000000,"","suCreateDate",2,out count,0);

            DataView dv2 = dt2.DefaultView;

            if(name!="")

            {

                /*

                if(begin==""&&end!="")

                {

                    dv1.RowFilter = "NickName='"+name+"'  and suCreateDate<='"+Convert.ToDateTime(end).AddDays(1)+"'";    

                    dv2.RowFilter = "NickName='"+name+"'  and suCreateDate<='"+Convert.ToDateTime(end).AddDays(1)+"'";                    

                }

                else if(end==""&&begin!="")

                {

                    dv1.RowFilter = "NickName='"+name+"' and suCreateDate>='"+begin+"'";    

                    dv2.RowFilter = "NickName='"+name+"' and suCreateDate>='"+begin+"'";                    

                }

                else if(begin==""&&end=="")

                {

                    Components.Tools.Utils.MessageBox("起止日期不能都为空！");

                    return;

                }

                else

                {

                    dv1.RowFilter = "NickName='"+name+"' and suCreateDate>='"+begin+"' and suCreateDate<='"+Convert.ToDateTime(end).AddDays(1)+"'";    

                    dv2.RowFilter = "NickName='"+name+"' and suCreateDate>='"+begin+"' and suCreateDate<='"+Convert.ToDateTime(end).AddDays(1)+"'";    

            

                }    

                */            

                string filter = "1=1 and 2=2";

                if(begin!="")

                    filter = filter.Replace("1=1","suCreateDate>='"+begin+"'");

                if(end != "")

                    filter = filter.Replace("2=2","suCreateDate<='"+Convert.ToDateTime(end).AddDays(1)+"'");

                dv1.RowFilter = "NickName='"+name+"' and " + filter;

                dv2.RowFilter = dv1.RowFilter;

                int Num1 = dv1.Count;        

                int Num2 = dv2.Count;

                int num = Num2+Num1;

                this.LabMessage.Text="该用户理财贴吧与随便贴吧发帖共"+num+"条";

            }            

            else

            {

                Components.Tools.Utils.MessageBox("用户名不能为空！");

            }

            DgBind();

        }