通用分页存储过程算法(.net类实现)

using System;

namespace CountryPark.DAL
{
    
/**//// <summary>
    
/// PageList 的摘要说明。
    
/// </summary>
    public sealed class PageList
    {
        
static PageList()
        {
        }
        
        
/**//// <summary>
        
/// 分页查询数据记录总数获取
        
/// </summary>
        
/// <param name="_tbName">----要显示的表或多个表的连接</param>
        
/// <param name="_ID">----主表的主键</param>
        
/// <param name="_strCondition">----查询条件,不需where</param>        
        
/// <param name="_Dist">----是否添加查询字段的 DISTINCT 默认0不添加/1添加</param>
        
/// <returns></returns>
        public static string getPageListCounts(string _tbName, string _ID, string _strCondition, int _Dist)
        {            
            
//---存放取得查询结果总数的查询语句                    
            
//---对含有DISTINCT的查询进行SQL构造
            
//---对含有DISTINCT的总数查询进行SQL构造
            string strTmp="", SqlSelect="", SqlCounts="";
            
            
if (_Dist == 0)
            {
                SqlSelect 
= "SELECT ";
                SqlCounts 
= "COUNT(*)";
            }
            
else
            {
                SqlSelect 
= "SELECT DISTINCT ";
                SqlCounts 
= "COUNT(DISTINCT "+ _ID +")";
            }
            
if (_strCondition == string.Empty)
            {
                strTmp 
= SqlSelect +" @Counts="+ SqlCounts +" FROM "+ _tbName;
            }
            
else
            {
                strTmp 
= SqlSelect +" @Counts="+ SqlCounts +" FROM "+ " WHERE (1=1) "+ _strCondition; 
            }
            
return strTmp;
        }


        
/**//// <summary>
        
/// 获取分页数据查询SQL
        
/// </summary>
        
/// <param name="_tbName">----要显示的表或多个表的连接</param>
        
/// <param name="_fldName">----要显示的字段列表</param>
        
/// <param name="_PageSize">----每页显示的记录个数</param>
        
/// <param name="_Page">----要显示那一页的记录</param>
        
/// <param name="_PageCount">----查询结果分页后的总页数</param>
        
/// <param name="_Counts">----查询到的记录数</param>
        
/// <param name="_fldSort">----排序字段列表或条件(如果是多字段排列Sort指代最后一个排序字段的排列顺序(最后一个排序字段不加排序标记)--程序传参如:' SortA Asc,SortB Desc,SortC ')</param>
        
/// <param name="_Sort">----排序方法,0为升序,1为降序</param>
        
/// <param name="_strCondition">----查询条件,不需where</param>
        
/// <param name="_ID">----主表的主键</param>
        
/// <param name="_Dist">----是否添加查询字段的 DISTINCT 默认0不添加/1添加</param>
        
/// <returns></returns>                                                                           
        public static string getPageListSql(string _tbName, string _fldName, int _PageSize, int _Page, out int _PageCount, int _Counts, string _fldSort, int _Sort, string _strCondition, string _ID, int _Dist)
        {                
            
string strTmp=""//---strTmp用于返回的SQL语句
            string SqlSelect="", strSortType="", strFSortType="";   

            
if (_Dist == 0)
            {
                SqlSelect 
= "SELECT ";            
            }
            
else
            {
                SqlSelect 
= "SELECT DISTINCT ";                
            }

            
if (_Sort == 0)
            {
                strFSortType 
= " ASC";
                strSortType 
= " DESC";
            }
            
else
            {
                strFSortType 
= " DESC";
                strSortType 
= " ASC";
            }

//            ----取得查询结果总数量-----
            int tmpCounts = 1;
            
if (_Counts != 0)
            {
                tmpCounts 
= _Counts;
            }
//          --取得分页总数
            _PageCount = (tmpCounts + _PageSize - 1)/_PageSize;
            
//    /**//**当前页大于总页数 取最后一页**/
            if (_Page > _PageCount)
            {
                _Page 
= _PageCount; 
            }
            
if (_Page <= 0)
            {
                _Page 
= 1;
            }
//          --/*-----数据分页2分处理-------*/
            int pageIndex = tmpCounts/_PageSize;
            
int lastCount = tmpCounts%_PageSize;
            
if (lastCount > 0)
            {
                pageIndex 
= pageIndex + 1;
            }
            
else
            {
                lastCount 
= _PageSize;
            }
            
if (_strCondition == string.Empty) // --没有设置显示条件
            {
                
if (pageIndex < 2 || _Page <= (pageIndex/2 + pageIndex%2))  //--前半部分数据处理
                {
                    
if (_Page == 1)
                    {
                        strTmp 
= SqlSelect +" TOP "+ _PageSize +" "+ _fldName +" FROM "+ _tbName +" ORDER BY "+ _fldSort +" "+ strFSortType;
                    }
                    
else
                    {
                        strTmp 
= SqlSelect +" TOP "+ _PageSize +" "+ _fldName +" FROM "+ _tbName +" WHERE "+ _ID +" <(SELECT MIN("+ _ID +") FROM ("+ SqlSelect +" TOP "+ _PageSize*(_Page-1+" "+ _ID +" FROM "+ _tbName +
                            
" ORDER BY "+ _fldSort +" "+ strFSortType +") AS TBMinID) ORDER BY "+ _fldSort +" "+ strFSortType;
                    }
                }
                
else
                {
                    _Page 
= pageIndex - _Page + 1//后半部分数据处理
                    if (_Page <= 1//--最后一页数据显示
                    {
                        strTmp 
= SqlSelect +" * FROM ("+ SqlSelect +" TOP "+ lastCount +" "+ _fldName +" FROM "+ _tbName +" ORDER BY "+ _fldSort +" "+ strSortType +") AS TempTB"+ " ORDER BY "+ _fldSort +" "+ strFSortType;
                    }
                    
else
                    {
                        strTmp 
= SqlSelect +" * FROM ("+ SqlSelect +" TOP "+ _PageSize +" "+ _fldName +" FROM "+ _tbName +
                            
" WHERE "+ _ID +" >(SELECT MAX("+ _ID +") FROM("+ SqlSelect +" TOP "+ (_PageSize*(_Page-2)+lastCount) +" "+ _ID +" FROM "+ _tbName +
                            
" ORDER BY "+ _fldSort +" "+ strSortType +") AS TBMaxID) ORDER BY "+ _fldSort +" "+ strSortType +") AS TempTB ORDER BY "+ _fldSort +" "+ strFSortType;
                    }
                }
            }
            
else // --有查询条件
            {
                
if (pageIndex < 2 || _Page <=(pageIndex/2 + pageIndex%2))//--前半部分数据处理
                {
                    
if (_Page == 1)
                    {
                        strTmp 
= SqlSelect +" TOP "+ _PageSize +" "+ _fldName +" FROM "+ _tbName +"WHERE 1=1 "+ _strCondition +" ORDER BY "+ _fldSort +" "+ strFSortType;
                    }
                    
else
                    {
                        strTmp 
= SqlSelect +" TOP "+ _PageSize +" "+ _fldName +" FROM "+ _tbName +
                            
" WHERE "+ _ID +" <(SELECT MIN("+ _ID +") FROM ("+ SqlSelect +" TOP "+ (_PageSize*(_Page-1)) +" "+ _ID +" FROM " +_tbName +
                            
" WHERE 1=1 "+ _strCondition +" ORDER BY "+ _fldSort +" "+ strFSortType +") AS TBMaxID) "+ _strCondition +
                            
" ORDER BY "+ _fldSort +" "+ strFSortType;                            
                    }
                }
                
else //--后半部分数据处理
                {
                    _Page 
= pageIndex-_Page+1;
                    
if (_Page <= 1//--最后一页数据显示
                    {
                        strTmp 
= SqlSelect +" * FROM ("+ SqlSelect +" TOP "+ lastCount +" "+ _fldName +" FROM "+ _tbName +
                            
" WHERE 1=1 "+ _strCondition +" ORDER BY "+ _fldSort +" "+ strSortType +") AS TempTB ORDER BY "+ _fldSort +" "+ strFSortType;
                    }
                    
else
                    {   
                        strTmp 
= SqlSelect +" * FROM ("+ SqlSelect +" TOP "+ _PageSize +" "+ _fldName +" FROM "+ _tbName +
                            
" WHERE "+ _ID +" >(SELECT MAX("+ _ID +") FROM("+ SqlSelect +" TOP "+ (_PageSize*(_Page-2)+ lastCount) +" "+ _ID +" FROM "+ _tbName +
                            
" WHERE 1=1 "+ _strCondition +" ORDER BY "+ _fldSort +" "+ strSortType +") AS TBMaxID) "+ _strCondition +
                            
" ORDER BY "+ _fldSort +" "+ strSortType +") AS TempTB ORDER BY "+ _fldSort +" "+ strFSortType;
                    }
                }
            }

            
return strTmp;
        }
    }
}
//--以上代码是针对之前写的TOP MAX模式的分页存储过程修改
//--以上分页算法对SQL SERVER 和 ACCESS同样有效


//调用函数例子
public IList getParkDataList(string key, int curPage, out int pageCount, int pageSize, int Counts)
{

IList list = new ArrayList();

string SECLECT_FIELD = "T_Park.ParkID, T_Park.ParkTitle, T_Park.ParkLetter, T_ParkArea.AreaName, T_ParkType.ParkTypeName ";
string SECLECT_TABLE = "T_ParkType INNER JOIN (T_ParkArea INNER JOIN T_Park ON T_ParkArea.ParkAreaID = T_Park.ParkAreaID) ON T_ParkType.ParkTypeID = T_Park.ParkTypeID";
string SECLECT_CONDITION = string.Empty;


if (key != string.Empty)
{
SECLECT_CONDITION = " AND T_Park.ParkTitle like '%"+ key +"%'";
}

string SELECT_ID = "ParkID";
string SELECT_FLDSORT = "ParkID";
int SELECT_SORT = 1;
int SELECT_DIST = 0;
string SQL = PageList.getPageListSql(SECLECT_TABLE, SECLECT_FIELD, pageSize, curPage, out pageCount, Counts, SELECT_FLDSORT, SELECT_SORT, SECLECT_CONDITION, SELECT_ID, SELECT_DIST);
//string strCondition;
OleDb db = new OleDb();
ParkBE park;
using(OleDbDataReader dr = (OleDbDataReader)db.ExecuteReader(CommonFun.GetConnectionString(), CommandType.Text, SQL))
{
while (dr.Read())
{
原文地址:https://www.cnblogs.com/zhuawang/p/784314.html