SQL实现模糊字段查询，去空版
select * from UTUserwhere (username like '%第一个textbox的值%' and len(username) > 0) or (password like '%第二个textbox的值%' and len(password) > 0) or (lasttime like '%第三个textbox的值%' and len(lasttime) > 0) or (usertype like '%第四个textbox的值%' and len(usertype) > 0)
