Question

asp中判断用户名已在数据库中存在

如果所填用户名已存在则提示用户名已存在，如果不存在就直接将用户名插入到数据库中..要怎么写？

Answer 1

试试如下代码：
username = request("username")
if isNull(username) then
username = ""
else
username = Trim(username)
end if
sql="select * from 用户表 where 姓名='"&username&"'"
set rs=server.createobject("adodb.recordset")
rs.open sql,conn,1,3
If rs.BOF And rs.EOF Then
rs.addnew
rs("姓名")=username
rs.update
rs.close
set rs=Nothing
response.write "<script language=javascript>"
response.write " alert('添加信息成功！');"
response.write " window.location='你想返回的页面.asp';"
response.write "</script>"
Else
rs("姓名")=username
rs.update
rs.close
set rs=Nothing
response.write "<script language=javascript>"
response.write " alert('信息修改成功');"
response.write " window.location='你返回的页面地址.asp';"
response.write "</script>"
End If

Answer 2

set rs=conn.execute("select * from [Users] where username='"&Trim(request("username"))&"'")
if not rs.eof then'表示已存在用户名
response.write "<script>alert('已存在的用户名');</script>"
else
conn.execute("insert into [Users](userid,username) values(1,'"&Trim(request("username"))&"')")
end if

Answer 3

写一个方法，从数据库表中读取到用户表用户名那一列，再判断是否存在。

Answer 4

你可以百度搜索呀