数据库中的null转换成其他

 

select A.UserId,A.UserName,A.Error,B.Name,isnull(B.Sfzh,'还未填写')Sfzh,B.Tell,B.Address,B.Age,(case B.General when 1 then '男' when 0 then '女' end)性别 from T_User A LEFT OUTER JOIN T_UserInfo B on A.UserId=B.UserId where

 

isnull 数据库中将为空的字段显示成还未填写

(case B.General when 1 then '男' when 0 then '女' end)性别将数据库中的bit类型中的true和folse转换成男女，比在数据库中的字段用varchar（20）节省空间

 

switch (comboBox1.Text)

            {

                case "姓名":

                    sqlwhere = "B.Name like @name";

                    cmd.Parameters.AddWithValue("@name", "%"+ textbox1.Text +"%");

                    break;

                case "用户名":

                    sqlwhere = "A.UserName like @username";

                    cmd.Parameters.AddWithValue("@username", "%" + textbox1.Text + "%");

                    break;

                case "电话":

                    sqlwhere = "B.Tell like @tell";

                    cmd.Parameters.AddWithValue("@tell", "%" + textbox1.Text + "%");

                    break;

                case "地址":

                    sqlwhere = "B.Address like @address";

                    cmd.Parameters.AddWithValue("@address", "%" + textbox1.Text + "%");

                    break;

                default:

                    sqlwhere = "B.Sfzh like @sfzh";

                    cmd.Parameters.AddWithValue("@sfzh", "%" + textbox1.Text + "%");

                    break;

            }

将占位符写在switch语句中的模糊查询