SqlSERVER分页函数补充了额外查询条件的处理

/**/ /// <summary>

        /// MS sqlSERVER 分页sql语句生成器，同样适用于ACCESS数据库(edit:2008.3.29)

        /// </summary>

        /// <param name="strsqlInfo">原始sql语句</param>

        /// <param name="strWhere">在分页前要替换的字符串，用于分页前的筛选</param>

        /// <param name="PageSize">页大小</param>

        /// <param name="PageNumber">页码</param>

        /// <param name="AllCount">记录总数</param>

        /// <returns>生成sql分页语句</returns>

         private   static   string  MakePagesqlStringByMSsql( string  strsqlInfo, string  strWhere, int  PageSize, int  PageNumber, int  AllCount)

         ... {

            分页位置分析#region 分页位置分析

            string strsqlType=string.Empty ;

            if(AllCount!=0)

            ...{

                if(PageNumber==1) //首页

                ...{

                    strsqlType="First";

                }

                else if(PageSize*PageNumber>AllCount) //最后的页 @@LeftSize

                ...{

                    PageSize=AllCount-PageSize*(PageNumber-1);

                    strsqlType="Last";

                }

                else //中间页

                ...{

                    strsqlType="Mid";

                }

            }

            else if(AllCount<0) //特殊处理 dth,2006.10.19

            ...{

                strsqlType="First";

            }

            else

            ...{

                strsqlType="Count";

            }

            #endregion

            

            sql 复杂度分析#region sql 复杂度分析 

            //sql 复杂度分析 开始

            bool sqlFlag=true;//简单sql标记

            string Testsql=strsqlInfo.toupper ();

            int n=Testsql.IndexOf ("SELECT ",0);

            n=Testsql.IndexOf ("SELECT ",n+7);

            if(n==-1)

            ...{

                //可能是简单的查询，再次处理

                n=Testsql.IndexOf (" JOIN ",n+7);

                if(n!=-1) sqlFlag=false;

                else

                ...{

                    //判断From 谓词情况

                    n=Testsql.IndexOf("FROM ",9);

                    if(n==-1) return "";

                    //计算 WHERE 谓词的位置

                    int m=Testsql.IndexOf ("WHERE ",n+5);

                    // 如果没有WHERE 谓词

                    if(m==-1) m=Testsql.IndexOf ("ORDER BY ",n+5);

                    //如果没有ORDER BY 谓词，那么无法排序，退出；

                    if(m==-1) 

                        throw new Exception ("查询语句分析：当前没有为分页查询指定排序字段！请适当修改sql语句。 "+strsqlInfo);

                    string strTableName=Testsql.Substring (n,m-n);

                    //表名中有 , 号表示是多表查询

                    if(strTableName.IndexOf (",")!=-1)

                        sqlFlag=false;

                }

            }

            else

            ...{

                //有子查询；

                sqlFlag=false;

            }

            //sql 复杂度分析 结束

            #endregion

            排序语法分析#region 排序语法分析

            //排序语法分析 开始

            int iOrderAt=strsqlInfo.ToLower ().LastIndexOf ("order by ");

            //如果没有ORDER BY 谓词，那么无法排序分页，退出；

            if(iOrderAt==-1)

                throw new Exception ("查询语句分析：当前没有为分页查询指定排序字段！请适当修改sql语句。 "+strsqlInfo);

            string strOrder=strsqlInfo.Substring (iOrderAt+9);

            strsqlInfo=strsqlInfo.Substring(0,iOrderAt);

            string[] strArrOrder=strOrder.Split (new char []...{','});

            for(int i=0;i<strArrOrder.Length ;i++)

            ...{

                string[] strArrTemp=(strArrOrder[i].Trim ()+" ").Split (new char[]...{' '});

                //压缩多余空格

                for(int j=1;j<strArrTemp.Length ;j++)

                ...{

                    if(strArrTemp[j].Trim ()=="")

                    ...{

                        continue;

                    }

                    else

                    ...{

                        strArrTemp[1]=strArrTemp[j];

                        if(j >1 ) strArrTemp[j]="";

                        break;

                    }

                }

                //判断字段的排序类型

                switch(strArrTemp[1].Trim ().toupper ())

                ...{

                    case "DESC":

                        strArrTemp[1]="ASC";

                        break;

                    case "ASC":

                        strArrTemp[1]="DESC";

                        break;

                    default:

                        //未指定排序类型，默认为降序

                        strArrTemp[1]="DESC";

                        break;

                }

                //消除排序字段对象限定符

                if(strArrTemp[0].IndexOf (".")!=-1)

                    strArrTemp[0]=strArrTemp[0].Substring (strArrTemp[0].IndexOf (".")+1);

                strArrOrder[i]=string.Join (" ",strArrTemp);

            }

            //生成反向排序语句

            string strNewOrder=string.Join (",",strArrOrder).Trim ();

            strOrder=strNewOrder.Replace ("ASC","ASC0").Replace ("DESC","ASC").Replace ("ASC0","DESC");

            //排序语法分析结束

            #endregion

            构造分页查询#region 构造分页查询

            string sql=string.Empty ;

            if(!sqlFlag)

            ...{

                //复杂查询处理

                switch(strsqlType.toupper ())

                ...{

                    case "FirsT":

                        sql="Select Top @@PageSize * FROM ( " +strsqlInfo+

                            " ) P_T0 @@Where ORDER BY "+strOrder;

                        break;

                    case "MID":

                        sql=@"SELECT Top @@PageSize * FROM

                         (SELECT Top @@PageSize * FROM

                           (

                             SELECT Top @@Page_Size_Number * FROM (";

                        sql+=" "+strsqlInfo+" ) P_T0 @@Where ORDER BY "+strOrder+" ";

                        sql+=@") P_T1

            ORDER BY "+ strNewOrder +") P_T2  "+

                            "ORDER BY "+strOrder;

                        break;

                    case "LAST":

                        sql=@"SELECT * FROM (     

                          Select Top @@LeftSize * FROM ("+" "+strsqlInfo+" ";

                        sql+=" ) P_T0 @@Where ORDER BY "+ strNewOrder+" "+ 

                            " ) P_T1 ORDER BY "+strOrder;

                        break;

                    case "COUNT":

                        sql="Select COUNT(*) FROM ( " +strsqlInfo+" ) P_Count @@Where";

                        break;

                    default:

                        sql=strsqlInfo+strOrder;//还原

                        break;

                }

            }

            else

            ...{

                //简单查询处理

                switch(strsqlType.toupper ())

                ...{

                    case "FirsT":

                        sql=strsqlInfo.toupper().Replace ("SELECT ","SELECT TOP @@PageSize "); 

                        sql+="  @@Where ORDER BY "+strOrder;

                        break;

                    case "MID":

                        string strRep=@"SELECT Top @@PageSize * FROM

                         (SELECT Top @@PageSize * FROM

                           (

                             SELECT Top @@Page_Size_Number  ";

                        sql=strsqlInfo.toupper().Replace ("SELECT ",strRep); 

                        sql+="  @@Where ORDER BY "+strOrder;

                        sql+="  ) P_T0 ORDER BY "+ strNewOrder+" "+ 

                            " ) P_T1 ORDER BY "+strOrder;

                        break;

                    case "LAST":

                        string strRep2=@"SELECT * FROM (     

                          Select Top @@LeftSize ";

                        sql=strsqlInfo.toupper().Replace ("SELECT ",strRep2);

                        sql+=" @@Where ORDER BY "+ strNewOrder+" "+ 

                            " ) P_T1 ORDER BY "+strOrder;

                        break;

                    case "COUNT":

                        sql="Select COUNT(*) FROM ( " +strsqlInfo+" @@Where) P_Count ";//edit 2008.3.29

                        break;

                    default:

                        sql=strsqlInfo+strOrder;//还原

                        break;

                }

            }

            //执行分页参数替换

            sql=sql.Replace ("@@PageSize",PageSize.ToString ())

                .Replace ("@@Page_Size_Number",Convert.ToString (PageSize * PageNumber))

                .Replace ("@@LeftSize",PageSize.ToString ());//

                //.Replace ("@@Where",strWhere);

            //针对用户的额外条件处理：

            if(strWhere!="" && strWhere.toupper ().Trim ().StartsWith ("WHERE "))

            ...{

                throw new Exception ("分页额外查询条件不能带Where谓词！");

            }

            if(!sqlFlag)

            ...{

                if(strWhere!="") strWhere=" Where "+strWhere;

                sql=sql.Replace ("@@Where",strWhere);

            }

            else

            ...{

                if(strWhere!="") strWhere=" And ("+strWhere+")";

                sql=sql.Replace ("@@Where",strWhere);

            }

            return sql;

            #endregion

        }