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();
        }