sql语句看不懂，高手来解释下

小幺鸡 2012-01-16 09:28:47

在网上下的strut1.2的图书馆系统源码，在这里出错了，返回的结果集为空，看半天不懂
public ArrayList getBooksList(int count, int page, String sqlstr) {
ArrayList list = new ArrayList();
try {
proc = conn.prepareCall("{call BooksPage (?,?,?,?)}");
proc.setInt(1, page);
proc.setInt(2, count);
proc.setString(3, sqlstr);
proc.registerOutParameter(4, Types.INTEGER);
res = proc.executeQuery();
while (res.next()) {
BooksBean bsb = new BooksBean();
bsb.setBooks_Amount(res.getInt("Books_Amount"));
bsb.setBooks_Company(res.getString("Books_Company"));
bsb.setBooks_Count(res.getInt("Books_Count"));
bsb.setBooks_ID(res.getInt("Books_ID"));
bsb.setBooks_Name(res.getString("Books_Name"));
bsb.setBooks_Time(res.getString("Books_Time"));
bsb.setBookType_ID(res.getInt("BookType_ID"));
list.add(bsb);
}
pagecount = proc.getInt(4);
} catch (SQLException ex) {
System.out.println("服务器异常发生在 getBooksList()");
ex.printStackTrace();
}
return list;
}
请大家赐教。。。。

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jnhcd 2012-01-17

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call BooksPage (?,?,?,?)}这个sql贴出来啊

haidilee 2012-01-17

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其实这个问题一点一点调试就可以了，断点就设在调用过程的后面一句，单步调试。看看哪里空掉了？我猜测是过程执行的时候哪个数据空掉了。所以呢，你可以去调试过程

五哥 2012-01-17

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你可以在查询分析器中执行 execute BooksPage (?,?,?,?)

问号用你的实际输入代替，执行一下就知道结果了；
4个问号的值分别赋值给 @curPage int=1,
@perPageRecords int,
@sqlstr varchar(255),
@countpage int output
这4个变量；

五哥 2012-01-17

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if exists (select 1 from sysobjects where id = object_id('total_count') and type = 'U') drop table total_count
---找到用户创建的表'total_count' ，如果存在了就删除掉，然后在创建一个 'total_count' ；
create table total_count(toll int)
execute( 'insert into total_count select count(*) from Books ' + @sqlstr)

---把查询出来的数据插入到'total_count' 表
select @total_count = toll from total_count

--查询出数据赋值给@total_count变量，然后把表'total_count'删除掉
drop table total_count
declare @page_in_show int
set @page_in_show=@total_count-(@curPage-1)*@perPageRecords
set @countpage=(@total_count+@perPageRecords -1)/@perPageRecords
exec('select top '+@perPageRecords+' * from (select top '+@page_in_show+' * from Books '+@sqlstr+' order by Books_ID desc) as a order by Books_ID asc')

你可以在查询分析器中执行 call BooksPage (?,?,?,?)

问号用你的实际输入代替，执行一下就知道结果了；
4个问号的值分别赋值给 @curPage int=1,
@perPageRecords int,
@sqlstr varchar(255),
@countpage int output
这4个变量；

小幺鸡 2012-01-17

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是这个么？我贴出Bookspage的好了



USE [Book]

GO

/****** Object:  StoredProcedure [dbo].[BooksPage]    Script Date: 01/17/2012 08:22:01 ******/

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

ALTER procedure [dbo].[BooksPage]

@curPage int=1,

@perPageRecords int,

@sqlstr varchar(255),

@countpage int output

as

declare @total_count int

if exists (select 1 from  sysobjects where  id = object_id('total_count') and   type = 'U') drop table total_count

create table total_count(toll int)

execute( 'insert into total_count select  count(*) from Books ' + @sqlstr)

select @total_count = toll from total_count

drop table total_count

declare @page_in_show int

set @page_in_show=@total_count-(@curPage-1)*@perPageRecords

set @countpage=(@total_count+@perPageRecords -1)/@perPageRecords 

exec('select top '+@perPageRecords+' * from (select top '+@page_in_show+' * from Books '+@sqlstr+' order by Books_ID desc) as a order by Books_ID asc')