首先写一段存储过程

        create procedure [proc_ChangePass]
            @UserName varchar(32) ,--用户名
            @OldPwd varchar(64) ,--旧密码
            @NewPwd varchar(64) ,--新密码
            @OutPut int output--输出参数,状态的判断
        as
            if exists ( select Id ,UserName from [jcms_normal_user] where UserName = @UserName )--用户存在,修改密码的条件
            begin
                --获取用户旧密码
                declare @_oldPwd varchar(64)
                set @_oldPwd = (select UserPass from [jcms_normal_user] where UserName = @UserName)
                 --判断用户旧密码
                if ( @OldPwd = @_oldPwd )
                begin
                    update [jcms_normal_user] set UserPass = @NewPwd where UserName = @UserName
                    set @OutPut = 1--旧密码正确.修改成功
                end
                else
                begin
                    set @OutPut = 2--用户存在,密码不正确,修改失败
                end
            end
            else
            begin
                set @OutPut = 3--用户不存在,无法修改
            end