select 语句的问题,对于懂得人挺容易的,对于一个新手来说,就是问题了,很急,在线等!

select a.proxy_id,b.proxy_name from proxy_table1 a,proxy_table2 b where a.proxy_id=b.proxy_id不好意思少了一个b

select b. proxy_name from proxy_table1 a,proxy_table2 b
where a.proxy_id=b.proxy_id

select a.id,b.proxy_name from proxy_table1 a inner join proxy_table2 b on a.proxy_id=b.proxy_id

a,b 表示两张表，你看一下sql的帮助，都有的。

a,b分别是proxy_table1,proxy_table2的别名.
不用a,b就要这么写了：
select proxy_table2.proxy_name
from proxy_table1 ,proxy_table2
where proxy_table1.proxy_id=proxy_table2.proxy_id

select a.proxy_id,b.proxy_name from proxy_table1 a,proxy_table2 b where a.proxy_id=b.proxy_id

select d. proxy_name from proxy_table1 c,proxy_table2 d
where c.proxy_id=d.proxy_id呵呵，不知道这样能不能打折？

字段        字段
proxy_table1,第一个表的字段,  proxy_id
proxy_table2,第二个表的字段,  proxy_id , proxy_name,
请问我该怎么用SELECT的语句判断取出表(proxy_id=proxy_id相同ID号的)proxy_table2的字段proxy_name的一个记录.如果取出来了后,我怎么在网页里显示出被取出来的那个(proxy_name)字段的记录.
要定义几个变量吗?
请多多指导,本人初次来使用JSP从库里提取数据.

如果是循环就：
<%while(rs.next()){
out.print(rs.getString("proxy_name"));
}%>

我这样写对不对:
<%
 if(strProxy.equals("1")){
 strSQL="select proxy_name from ill.lib_transaction_"+lib_code+",ill.proxy_range_table where proxy_id = proxy_id";
}


 %>
<%=rs.getString("proxy_name")%>

要不要定义变量给他,出下面的错误,什么意思?
An error occurred at line: 298 in the jsp file: /member/case_trans/case0_print.jspGenerated servlet error:
/export/home/www/tomcat/work/Standalone/localhost/_/member/case_trans/case0_0005fprint$jsp.java:628: Undefined variable: proxyrange_name
                out.print(proxyrange_name);
                          ^
Note: /export/home/www/tomcat/work/Standalone/localhost/_/member/case_trans/case0_0005fprint$jsp.java uses or overrides a deprecated API.  Recompile with "-deprecation" for details.
1 error, 2 warnings

靠，你写的什么东西，你的proxyrange_name当然是一个变量了。

分两部分贴
<%@ page contentType="text/html;charset=gb2312" %>
<%@ page import="java.io.*"%>
<%@ page import="java.util.*"%>
<%@ page import="java.sql.*"%>
<%@ page session="true"%>
<%@include file="../../security.jsp"%>
<jsp:useBean id="interll_sql" class="sql.interll_sql" />
<jsp:useBean id="interll_sql_page" class="sql.interll_sql" />
<jsp:useBean id="strtool" scope="page" class="freshsky.strtool" />
<jsp:useBean id="foo" scope="page" class="checkbox.check"/>
<jsp:setProperty name="foo" property="choise" param="checkb" />
<jsp:useBean id="p_db" scope="page" class="sql.P_DB"/>
<jsp:useBean id="db" class="sql.interll_sql" />
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
<html>
<head>
<title>事务信息打印</title>
<meta http-equiv="Content-Type" CONTENT="text/html;charset=gb2312">
<link href="../../include/styles.css" rel="stylesheet" type="text/css">
</head><body bgcolor="#F9F9F3" topmargin=0 leftmargin=0 marginwidth=0 marginheight=0 onLoad='window.print()'>
<%
//取得当前操作员session,变成变量
java.lang.String oper_code=(String)session.getAttribute("ill_id");
java.lang.String lib_code=(String)session.getAttribute("ill_lib");
java.lang.String oper_name=(String)session.getAttribute("ill_username");
java.lang.String oper_ip=(String)session.getAttribute("ip_addr");java.lang.String lib_shortname=(String)session.getAttribute("ill_libshortname");try{
java.sql.ResultSet sqlRst=null; //结果集对象
java.lang.String strSQL=""; //SQL语句
java.lang.String sqlRst2=null;
//********************************************3-13
//java.lang.String strSql = "";
//java.sql.ResultSet RsFeast = null;
//java.lang.String strName = "";
//java.lang.String strId = "";//strSql = "select * from ill.proxy_range_table ";
//RsFeast = db.executeQuery(strSql);
//if (null == RsFeast) {
// response.sendRedirect("/error.jsp?msg='读取错误！'");
// return;
// }
// RsFeast.last();
//out.println(strSql);//*******************************************3-14int i=0;
String[] checkStr;int checkId = 0;//当前打印记录号
int checkMax = 0;//打印条数
//sqlSQL="select lib_transaction_"+ lib_code +".* from ill.lib_transaction_" +lib_code+ "";
if( request.getParameter("checkb") != null){
session.removeAttribute("checkStr");
checkStr = foo.getchoise();
session.setAttribute("checkStr",checkStr);
}
else if( session.getAttribute("checkStr")!= null){
checkStr=(String[])session.getAttribute("checkStr");
}
else{
checkStr = new String[]{"-1"};
}java.lang.String sub = str_BlankNull( (String)request.getParameter("sub") );
if(sub.equals("print") || sub.equals(""))
sub = "0";checkMax = checkStr.length-1;
checkId = Integer.valueOf(sub).intValue();
java.lang.String ariel = "";
String req_transid ="";
java.lang.String trans_id="";
java.lang.String res_transid="";
java.lang.String ill_barcode="";
java.lang.String cen_rec_id="";
java.lang.String circul_rec_id="";
java.lang.String req_lib_code="";
java.lang.String res_lib_code="";
java.lang.String send_type="";
java.lang.String record_type="";
java.lang.String pages="";
java.lang.String ill_fee="";
java.lang.String quick_check="";
java.lang.String ill_return="";
java.lang.String date_due="";//到期时间?????
java.lang.String res_http="";
java.lang.String local_http="";
java.lang.String title="";
java.lang.String class_no="";
java.lang.String publish_year="";
java.lang.String rec_volno="";
java.lang.String language="";
java.lang.String req_date="";
java.lang.String receibe_date="";
java.lang.String input_date="";
java.lang.String trans_status="";
java.lang.String req_note="";
java.lang.String res_note="";
java.lang.String trans_note="";
java.lang.String local_shortname="";
java.lang.String remote_shortname="";
java.lang.String book_search_no="";
java.lang.String res_libcode="";
java.lang.String req_libcode="";
java.lang.String oper_date="";
java.lang.String transId="";
java.lang.String m_pages="";
java.lang.String status_desc="";
java.lang.String abs_title="";
java.lang.String abs_author="";
java.lang.String abs_pagesnote="";
java.lang.String reader_refno="";
java.lang.String faxno="";
java.lang.String email="";
java.lang.String post_zip="";
java.lang.String post_add="";
java.lang.String addressee="";
java.lang.String order_id="";
String strProxy = "0"; //**************************************************03-13//String strProxy_id = ""; //****************************3-14
//生成资料类型内容，二维数组arrayRec存入session
String[][] arrayRec;
strSQL = "select * from ill.recordtype_table order by record_type";
sqlRst=interll_sql.executeQuery(strSQL);
if (sqlRst !=null){
sqlRst.last();
int rec_num = sqlRst.getRow();
arrayRec = new String[rec_num+1][2];
sqlRst.beforeFirst();
for (i=0; i < rec_num; i++)
if (sqlRst.next()){
arrayRec[i][0]=str_BlankNull( sqlRst.getString("record_name") );
arrayRec[i][1]=str_BlankNull( sqlRst.getString("record_type") );
}
sqlRst.close();
}
else
arrayRec = new String[1][2];
interll_sql.close();
arrayRec[arrayRec.length-1][0]="";
arrayRec[arrayRec.length-1][1]="";
//结束生成资料类型内容//生成投递方式内容，二维数组arraySend
String[][] arraySend;
strSQL = "select send_type,send_typename from ill.sendtype_table order by send_type";
sqlRst=interll_sql.executeQuery(strSQL);
if (sqlRst !=null){
sqlRst.last();
int send_num = sqlRst.getRow();
arraySend = new String[send_num+1][2];
sqlRst.beforeFirst();
for (i=0; i < send_num; i++)
if (sqlRst.next()){
arraySend[i][0]=str_BlankNull( sqlRst.getString("send_typename") );
arraySend[i][1]=str_BlankNull( sqlRst.getString("send_type") );
}
sqlRst.close();
}
else
arraySend = new String[1][2];
interll_sql.close();
arraySend[arraySend.length-1][0]="";
arraySend[arraySend.length-1][1]="";
//结束生成投递方式内容req_transid = checkStr[checkId]; //***********************************************
strSQL="select * from ill.lib_transaction_"+lib_code+" where req_transid='"+req_transid+"'";
sqlRst=interll_sql.executeQuery(strSQL); //***********************03-13 //馆请求类型
if (sqlRst==null){
interll_sql.close();
response.sendRedirect("../../error.jsp?msg=结果集为空");
return;
}
%>

<%
if(checkId > 0)
out.println("<a href=\"case0_print.jsp?sub="+(checkId-1)+"\">【打印上一条】</a>");
%>
 <a href="javascript: window.print();">【打印】</a>
<%
if(checkId < checkMax)
out.println("<a href=\"case0_print.jsp?sub="+(checkId+1)+"\">【打印下一条】</a>");
%>
 <a href="javascript:window.close();">【关闭】</a>

第<%=checkId+1%>/<%=checkMax+1%>条    
本馆事务号: <%=req_transid%>    

<%
if(sqlRst.next()){
req_transid = str_BlankNull( sqlRst.getString("req_transid") );
local_shortname = str_BlankNull( sqlRst.getString("local_shortname") );
remote_shortname = str_BlankNull( sqlRst.getString("remote_shortname") );
ill_return = str_BlankNull( sqlRst.getString("ill_return") );
send_type = str_BlankNull( sqlRst.getString("send_type") );
record_type = str_BlankNull( sqlRst.getString("record_type") );
pages = str_BlankNull( sqlRst.getString("pages") );
quick_check = str_BlankNull( sqlRst.getString("quick_check") );
ill_fee = str_BlankNull( sqlRst.getString("ill_fee") );
res_http = str_BlankNull( sqlRst.getString("res_http") );
local_http = str_BlankNull( sqlRst.getString("local_http") );
title = str_BlankNull( sqlRst.getString("title") );
language = str_BlankNull( sqlRst.getString("language") );
class_no = str_BlankNull( sqlRst.getString("class_no") );
book_search_no = str_BlankNull( sqlRst.getString("book_search_no") );
rec_volno = str_BlankNull( sqlRst.getString("rec_volno") );
req_date = str_BlankNull( sqlRst.getString("req_date") );
req_note = str_BlankNull( sqlRst.getString("req_note") );
res_note = str_BlankNull( sqlRst.getString("res_note") );
trans_note = str_BlankNull( sqlRst.getString("trans_note") );
publish_year = str_BlankNull( sqlRst.getString("publish_year") );
res_transid = str_BlankNull( sqlRst.getString("res_transid") );
ill_barcode = str_BlankNull( sqlRst.getString("ill_barcode") );
cen_rec_id = str_BlankNull( sqlRst.getString("cen_rec_id") );
circul_rec_id = str_BlankNull( sqlRst.getString("circul_rec_id") );
trans_id = str_BlankNull( sqlRst.getString("trans_id") );
trans_status = str_BlankNull( sqlRst.getString("trans_status") ); oper_date=p_db.get_sysdate("");
req_libcode = str_BlankNull( sqlRst.getString("req_libcode") );
res_libcode = str_BlankNull( sqlRst.getString("res_libcode") ); abs_title = str_BlankNull( sqlRst.getString("abs_title") );
abs_author = str_BlankNull( sqlRst.getString("abs_author") );
abs_pagesnote = str_BlankNull( sqlRst.getString("abs_pagesnote") ); faxno = str_BlankNull( sqlRst.getString("faxno") );
email = str_BlankNull( sqlRst.getString("email") );
post_zip = str_BlankNull( sqlRst.getString("post_zip") );
post_add = str_BlankNull( sqlRst.getString("post_add") );
addressee = str_BlankNull( sqlRst.getString("addressee") );
order_id = str_BlankNull( sqlRst.getString("order_id") );

//***************************03-13
strProxy = sqlRst.getString("trans_proxy");
if(null == strProxy) strProxy = "0";
strProxy = strProxy.trim();
//****************************03-13//***************************3-14
 //strProxy_id = sqlRst.getString("trans_proxy");
 //if(null == strProxy_id) strProxy_id = "0";
 //strProxy = strProxy_id.trim();
//*************************
interll_sql.close();
//ariel_ip
strSQL="select l.* from ill.lib_information l, ill.reader r where l.lib_code=r.lib_code and r.ill_barcode='"+ill_barcode+"'";
sqlRst=interll_sql.executeQuery(strSQL);
if (sqlRst !=null)
if (sqlRst.next())
ariel = str_BlankNull( sqlRst.getString("ariel_ip") );
interll_sql.close();%>
 <table class="green_t" width="550" border=0 cellPadding=0 cellSpacing=0 align="center">
 <tr height="25">
 <td nowrap align="right" width="110">申请单号: </td>
 <td width="165"><%=order_id%></td>
 <td nowrap align="right" width="110">求借日期: </td>
 <td width="165"><%=req_date%></td>
 </tr>
 <TR>
 <td nowrap alignt="right" valign="top"><div align="right">请求类型:</div></TD>
 <td><%= (strProxy.equals("1"))? "委托代查" : "普通申请" %> </td>
 
 </tr>


 <tr height="25">
 <td nowrap align="right" valign="top">申请单备注: </td>
 <td colspan=3 ><%=req_note%></td>
 </tr>
 <tr><td><%
 if(strProxy.equals("1")){
 strSQL="select proxyrange_name from ill.lib_transaction_"+lib_code+",ill.proxy_range_table where proxy_id = proxy_id";
}


 %>
<%=proxyrange_name%>
 <tr height="25">
 </tr>
 <tr><td colspan=4 height="1" background="../../images/doc_01.gif"></td></tr>
 <tr><td height="10"></td></tr> <tr height="25">
 <td nowrap align="right">索书号: </td>
 <td><%=book_search_no%></td>
 <td nowrap align="right">页码说明: </td>
 <td><%=abs_pagesnote%></td>
 </tr>
 <tr height="25">
 <td nowrap align="right">文章名: </td>
 <td colspan="3"><%=abs_title%></td>
 </tr>
 <tr height="25">
 <td nowrap align="right">文章作者: </td>
 <td colspan="3"><%=abs_author%></td>
 </tr>
 <tr height="25">
 <td nowrap align="right">文献名: </td>
 <td colspan="3"><%=title%></td>
 </tr>
 <tr height="25">
 <td nowrap align="right">文献卷期: </td>
 <td><%=rec_volno%></td>
 <td nowrap align="right">文献类型: </td>
 <td><%
for (int j=0; j < arrayRec.length-1; j++)
out.println( (record_type.equals(arrayRec[j][1])?(arrayRec[j][0]):"") );%>
 </td>
 </tr>
 <tr height="25">
 <td nowrap align="right">文献语种: </td>
 <td><%
if(language.equals("chi")) out.print("中文");
else if(language.equals("eng")) out.print("英文");
else if(language.equals("jap")) out.print("日文");
else if(language.equals("rus")) out.print("俄文");
else if(language.equals("oth")) out.print("其他");
%></td>
 <td nowrap align="right">文献分类: </td>
 <td><%=class_no%></td>
 </tr>
 <tr height="25">
 <td nowrap align="right">出版年代: </td>
 <td><%=publish_year%></td>
 </tr>

调试易

select 语句的问题,对于懂得人挺容易的,对于一个新手来说,就是问题了,很急,在线等!

解决方案 »