淺談mssql access數據庫 top分頁辦法。本站提示廣大學習愛好者：（淺談mssql access數據庫 top分頁辦法）文章只能為提供參考，不一定能成為您想要的結果。以下是淺談mssql access數據庫 top分頁辦法正文
然則有益也有弊，它請求排序字段必需組成獨一記載，且select後的字段列表中，不許可湧現與排序字段同名的字段。
固然sql2k5及以上版本曾經供給了rownum()來停止分頁處置，然則應用sql2k停止開辟的照樣較多的
uusing system.collections.generic;
sing system;
using system.text;
/// <summary>
/// 結構分頁後的sql語句
/// </summary>
public static class paginghelper
{
/// <summary>
/// 獲得分頁sql語句，排序字段須要組成獨一記載
/// </summary>
/// <param name="_recordcount">記載總數</param>
/// <param name="_pagesize">每頁記載數</param>
/// <param name="_pageindex">以後頁數</param>
/// <param name="_safesql">sql查詢語句</param>
/// <param name="_orderfield">排序字段，多個則用“,”離隔</param>
/// <returns>分頁sql語句</returns>
public static string createpagingsql(int _recordcount, int _pagesize, int _pageindex, string _safesql, string _orderfield)
{
//從新組合排序字段，避免有毛病
string[] arrstrorders = _orderfield.split(new char[] { ',' }, stringsplitoptions.removeemptyentries);
stringbuilder sboriginalorder = new stringbuilder(); //原排序字段
stringbuilder sbrever搜索引擎優化教程rder = new stringbuilder(); //與原排序字段相反，用於分頁
for (int i = 0; i < arrstrorders.length; i++)
{
arrstrorders[i] = arrstrorders[i].trim(); //去除前後空格
if (i != 0)
{
sboriginalorder.append(", ");
sbrever搜索引擎優化rder.append(", ");
}
sboriginalorder.append(arrstrorders[i]);
int index = arrstrorders[i].indexof(" "); //斷定能否有起落標識
if (index > 0)
{
//調換起落標識，分頁所需
bool flag = arrstrorders[i].indexof(" desc", stringcomparison.ordinalignorecase) != -1;
sbrever搜索引擎優化rder.appendformat("{0} {1}", arrstrorders[i].remove(index), flag ? "asc" : "desc");
}
else
{
sbrever搜索引擎優化rder.appendformat("{0} desc", arrstrorders[i]);
}
}
//盤算總頁數
_pagesize = _pagesize == 0 ? _recordcount : _pagesize;
int pagecount = (_recordcount + _pagesize - 1) / _pagesize;
//檢討以後頁數
if (_pageindex < 1)
{
_pageindex = 1;
}
else if (_pageindex > pagecount)
{
_pageindex = pagecount;
}
stringbuilder sbsql = new stringbuilder();
//第一頁時，直接應用top n，而不停止分頁查詢
if (_pageindex == 1)
{
sbsql.appendformat(" select top {0} * ", _pagesize);
sbsql.appendformat(" from ({0}) as t ", _safesql);
sbsql.appendformat(" order by {0} ", sboriginalorder.tostring());
}
//最初一頁時，削減一個top n
else if (_pageindex == pagecount)
{
sbsql.append(" select * from ");
sbsql.append(" ( ");
sbsql.appendformat(" select top {0} * ", _recordcount - _pagesize * (_pageindex - 1));
sbsql.appendformat(" from ({0}) as t ", _safesql);
sbsql.appendformat(" order by {0} ", sbrever搜索引擎優化rder.tostring());
sbsql.append(" ) as t ");
sbsql.appendformat(" order by {0} ", sboriginalorder.tostring());
}
//前半頁數時的分頁
else if (_pageindex < (pagecount / 2 + pagecount % 2))
{
sbsql.append(" select * from ");
sbsql.append(" ( ");
sbsql.appendformat(" select top {0} * from ", _pagesize);
sbsql.append(" ( ");
sbsql.appendformat(" select top {0} * ", _pagesize * _pageindex);
sbsql.appendformat(" from ({0}) as t ", _safesql);
sbsql.appendformat(" order by {0} ", sboriginalorder.tostring());
sbsql.append(" ) as t ");
sbsql.appendformat(" order by {0} ", sbrever搜索引擎優化rder.tostring());
sbsql.append(" ) as t ");
sbsql.appendformat(" order by {0} ", sboriginalorder.tostring());
}
//後半頁數時的分頁
else
{
sbsql.appendformat(" select top {0} * from ", _pagesize);
sbsql.append(" ( ");
sbsql.appendformat(" select top {0} * ", ((_recordcount % _pagesize) + _pagesize * (pagecount - _pageindex)));
sbsql.appendformat(" from ({0}) as t ", _safesql);
sbsql.appendformat(" order by {0} ", sbrever搜索引擎優化rder.tostring());
sbsql.append(" ) as t ");
sbsql.appendformat(" order by {0} ", sboriginalorder.tostring());
}
return sbsql.tostring();
}
/// <summary>
/// 獲得記載總數sql語句
/// </summary>
/// <param name="_n">限制記載數</param>
/// <param name="_safesql">sql查詢語句</param>
/// <returns>記載總數sql語句</returns>
public static string createtopnsql(int _n, string _safesql)
{
return string.format(" select top {0} * from ({1}) as t ", _n, _safesql);
}
/// <summary>
/// 獲得記載總數sql語句
/// </summary>
/// <param name="_safesql">sql查詢語句</param>
/// <returns>記載總數sql語句</returns>
public static string createcountingsql(string _safesql)
{
return string.format(" select count(1) as recordcount from ({0}) as t ", _safesql);
}
}
