<!--#include file="conn.asp"-->
<%  Diary_Title=request.Form("Diary_Title")
    Diary_Content=request.Form("Diary_Content")
    Diary_List_Title=request.Form("Diary_List_Title")
    Diary_List_Id=request.Form("Diary_List_Id")
    set rsn=server.CreateObject("ADODB.Recordset")
    sqn="select * from Diary_List where Diary_List_Id="&request("Diary_List_Id")
    rsn.open sqn,conn,1,1
    Diary_List_Title=rsn("Diary_List_Title")
    sql="insert into Diary(Diary_Title,Diary_Content,Diary_List_Title,Diary_List_Id,People_Id) values('"&Diary_Title&"','"&Diary_Content&"','"&Diary_List_Title&"','"&Diary_List_Id&"','"&session("People_Id")&"')"
   response.Write sql
   conn.execute(sql)
   response.write "<script language=JavaScript>" & chr(13) & "alert('添加日志文章成功.！');"&"window.location.href = 'liuyan.asp'"&"</script>"
   'sqll="insert into system_diary(people_name) values('"&people_name&"')
%>   
Microsoft JET Database Engine (0x80040E14)
语法错误 (操作符丢失) 在查询表达式 'Diary_List_Id=' 中。

Diary_List_Id=request.Form("Diary_List_Id")
Response.Write Diary_List_Id
检查Diary_List_Id,应该是值没有传过来

sql="insert into Diary(Diary_Title,Diary_Content,Diary_List_Title,Diary_List_Id,People_Id) values('"&Diary_Title&"','"&Diary_Content&"','"&Diary_List_Title&"','"&Diary_List_Id&"','"&session("People_Id")&"')"
   response.Write sql
   conn.execute(sql)

如果你的数据库字段Diary_List_Id为数字型请将'"&Diary_List_Title&"'改为"&Diary_List_Title&"赋值,注意字段类型

就是按你的方法做了之后，没有错误提示也没有值输出应该怎么改呢？谢谢

就是因为没有值输出所以才是错的，说明值没有传过来。检查一下form表单

<form name="form1" method="post" action="add_user_article.asp">
          <table width="100%"  border="0" cellspacing="0" cellpadding="0">
            <tr>
              <td height="40">文章的标题：
                <input name="Diary_Title" type="text" id="Diary_Title" size="25" maxlength="25"></td>
            </tr>
            <tr>
              <td height="40"><div align="center">
                  <textarea name="Diary_Conten" cols="74" rows="20" id="Diary_Content"></textarea>
                　　　　
              </div></td>
            </tr>
            <tr>
              <td height="40">选择添加目录：
                <select name="Diary_List_Title" id="Diary_List_Title">
                    <% set rsn=server.CreateObject("ADODB.Recordset")
                     sqn="select * from Diary_List"
                     rsn.open sqn,conn,1,1
                     do while not rsn.eof
                        response.Write "<option value="&rsn("Diary_List_Id")
                     response.Write ">"&rsn("Diary_List_Title")&"</option>"
                     rsn.movenext
                     loop
                 %>
                </select></td>
            </tr>
            <tr>
              <td height="40"><div align="center">
                  <input type="submit" name="Submit" value="添加">
              </div></td>
            </tr>
          </table>
      </form></td>
麻烦看一下我找不出什么地方错了呢？谢谢！！

数据库中Diary_List_Id是什么类型?

<select name="Diary_List_Title" id="Diary_List_Title">
                    <% set rsn=server.CreateObject("ADODB.Recordset")
                     sqn="select * from Diary_List"
                     rsn.open sqn,conn,1,1
                     do while not rsn.eof
                        response.Write "<option value="&rsn("Diary_List_Id")&">"
                     response.write ""&rsn("Diary_List_Title")&"</option>"
                     rsn.movenext
                     loop
                 %>
                </select>