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  • sql分页

    @PageIndex int, --第几页,第一页为1;
    @PageSize int, --页面大小;
    @TotalCount int OUTPUT, --总条数 输出参数;
     
     DECLARE @StartRowNum int;
     DECLARE @EndRowNum int;
     SET @StartRowNum=(@PageIndex-1)*@PageSize+1;
     SET @EndRowNum=@PageIndex*@PageSize;
     
     SELECT  
    		@TotalCount =COUNT(1) 
    		FROM   tableName
    		
    		WITH Temp AS 
    		(
    			SELECT TOP (@PageSize*@PageIndex) 
    				ID,
    				ROW_NUMBER() OVER (ORDER BY ID DESC)  AS RowNum  
    			FROM tableName			 
    				   
    		)
     SELECT 
    			*      
    		FROM Temp AS T 
    		INNER JOIN tableName tb ON T.Id=tb.Id 
    		WHERE T.RowNum BETWEEN @StartRowNum AND @EndRowNum 
    		ORDER BY RowNum 
    		或者直接
    		SELECT * FROM (SELECT *, ROW_NUMBER() OVER (ORDER BY ID DESC)  AS RowNum   FROM tbName) a where RowNum>=@StartRowNum  and RowNum<= @EndRowNum 
    
     

    按后面一种写法 也就是一条正常的sql语句,只要取得Orderby的字段,将row_number()拼接到他的select列中。然后select一下就行了。

    C#代码如下

     
     public static string GetPagedSql(string sql, int pageIndex, int pageSize )
          {
              if (String.IsNullOrEmpty(sql))
              {
                  return null;
              }      
                  string start = "0";
                  if (pageIndex > 0)
                  {
                      start = Convert.ToString(pageIndex * pageSize);
                  }
                  int select =  sql.GetSymPosition("select");                  
                      string end = Convert.ToString((pageIndex + 1) * pageSize);
                      string orderSql = sql.GetStrBySym("order by");
                      //fromwhere部分 含from、join及where部分group by 但不含order by
                      string fromSql =  sql.GetStrBySym( "from"); 
                      //select部分 含select
                      string selectSql = "select " + sql.Substring(select, sql.Length - select - fromSql.Length);
                      if (!String.IsNullOrEmpty(orderSql))
                      {
                          fromSql = fromSql.Substring(0, fromSql.Length - orderSql.Length);
                      }
                      else
                      {
                          throw new Exception( " sql2005 怎么着也得弄个order by啊");
                      }
                      //合并成分页SQL
                      string strSql = "select * from (" + selectSql;
                      //order部分 含 order by
                      string rownum  = "row_number()";
                       
                      strSql += "," + rownum + " over (" + orderSql + ") as rn " + fromSql
                             + ") as data where rn>" + start + " and rn<=" + end;
                      if (!String.IsNullOrEmpty( fromSql.GetStrBySym( "group by")) )
                     
                      {
                          fromSql = " from (select count(*) totalCount " + fromSql + ") tbl";
                      }
                      return strSql + ";select count(*) as totalCount " + fromSql;
              
          }
    
     public static  class ExtMethod
        {
            public static int GetCount(this string str, string sym)
            {
                if (String.IsNullOrEmpty(str) || String.IsNullOrEmpty(sym))
                {
                    return 0;
                }
                else
                {
                    return str.Length - str.Replace(sym, "").Length;
                }
            }
            public static int GetSymPosition(this string str,string sym)
            {
                if (String.IsNullOrEmpty(str) || String.IsNullOrEmpty(sym))
                {
                    return 0;
                }
                else
                {
                    Regex regex = new Regex(@"^[\s\n]*?(?<key>" + sym + @")[\[\(\s\n]+?.*?$", RegexOptions.IgnoreCase | RegexOptions.Multiline | RegexOptions.Compiled);
                    if (regex.IsMatch(str))
                    {
                        return regex.Match(str).Groups["key"].Index + sym.Length;
                    }
                    else
                    {
                        return 0;
                    }
                }
            }
            public static string GetStrBySym(this string str,string sym)
            {
                if (String.IsNullOrEmpty(str) || String.IsNullOrEmpty(sym))
                {
                    return null;
                }
                else
                {
                    string result = null;
                    Regex regex = new Regex(@"^.*?[\]\)\s\n\*]+?(?<key>" + sym + @")[\[\(\s\n\*]+?.*?$", RegexOptions.IgnoreCase | RegexOptions.Multiline | RegexOptions.Compiled);
                    if (regex.IsMatch(str))
                    {
                        bool isHas = false;
                        result = str;
                        while (regex.IsMatch(result))
                        {
                            result = result.Substring(regex.Match(result).Groups["key"].Index);
                            if (GetCount(result, "(") == GetCount(result, ")"))
                            {
                                isHas = true;
                                break;
                            }
                        }
                        if (!isHas)
                        {
                            result = null;
                        }
                    }
                    return result;
                }
            }
        }
    
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  • 原文地址:https://www.cnblogs.com/fuhui/p/1940947.html
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