興味深いページング・ストレージ・プロシージャ

CREATE procedure main_table_pwqzc
(@pagesize int,
@pageindex int,
@docount bit,
@this_id)
as
if(@docount=1)
begin
select count(id) from luntan where this_id=@this_id
end
else
begin
declare @indextable table(id int identity(1,1),nid int)
declare @PageLowerBound int
declare @PageUpperBound int
set @PageLowerBound=(@pageindex-1)*@pagesize
set @PageUpperBound=@PageLowerBound+@pagesize
set rowcount @PageUpperBound
insert into @indextable(nid) select id from luntan where this_id=@this_id order by reply_time desc
select a.* from luntan a,@indextable t where a.id=t.nid
and t.id>@PageLowerBound and t.id<=@PageUpperBound order by t.id
end
GO

 
ストレージ・プロシージャは、入力されたパラメータ@docountに基づいて、特にこの2行set rowcount@PageUpperBoundinsert into@indextable(nid)select id from luntan where this_を返すかどうかを決定します.id=@this_id order by reply_time desc
本当に素晴らしい!!set rowcount@PageUpperBoundレコード数が@PageUpperBoundに達するとクエリーの処理が停止し、select idはid列のみを一時表に取り出し、select a.*from luntan a,@indextable t where a.id=t.nidand t.id>@PageLowerBound and t.id<=@PageUpperBound order by.idとなり、この文もすべてのレコードではなくテーブルから必要なレコードのみを取り出し、結合すると、極めて効率を高めました!!すばらしい、本当にすばらしい!!!

CREATE PROCEDURE Paging_RowCount
(
@Tables varchar(1000),
@PK varchar(100),
@Sort varchar(200) = NULL,
@PageNumber int = 1,
@PageSize int = 10,
@Fields varchar(1000) = '*',
@Filter varchar(1000) = NULL,
@Group varchar(1000) = NULL)
AS
/*Default Sorting*/
IF @Sort IS NULL OR @Sort = ''
 SET @Sort = @PK
/*Find the @PK type*/
DECLARE @SortTable varchar(100)
DECLARE @SortName varchar(100)
DECLARE @strSortColumn varchar(200)
DECLARE @operator char(2)
DECLARE @type varchar(100)
DECLARE @prec int
/*Set sorting variables.*/ 
IF CHARINDEX('DESC',@Sort)>0
 BEGIN
  SET @strSortColumn = REPLACE(@Sort, 'DESC', '')
  SET @operator = '<='
 END
ELSE
 BEGIN
  IF CHARINDEX('ASC', @Sort) = 0
   SET @strSortColumn = REPLACE(@Sort, 'ASC', '')
  SET @operator = '>='
 END

IF CHARINDEX('.', @strSortColumn) > 0
 BEGIN
  SET @SortTable = SUBSTRING(@strSortColumn, 0, CHARINDEX('.',@strSortColumn))
  SET @SortName = SUBSTRING(@strSortColumn, CHARINDEX('.',@strSortColumn) + 1, 
LEN(@strSortColumn))
 END
ELSE
 BEGIN
  SET @SortTable = @Tables
  SET @SortName = @strSortColumn
 END
SELECT @type=t.name, @prec=c.prec
FROM sysobjects o 
JOIN syscolumns c on o.id=c.id
JOIN systypes t on c.xusertype=t.xusertype
WHERE o.name = @SortTable AND c.name = @SortName
IF CHARINDEX('char', @type) > 0
   SET @type = @type + '(' + CAST(@prec AS varchar) + ')'
DECLARE @strPageSize varchar(50)
DECLARE @strStartRow varchar(50)
DECLARE @strFilter varchar(1000)
DECLARE @strSimpleFilter varchar(1000)
DECLARE @strGroup varchar(1000)
/*Default Page Number*/
IF @PageNumber < 1
 SET @PageNumber = 1
/*Set paging variables.*/
SET @strPageSize = CAST(@PageSize AS varchar(50))
SET @strStartRow = CAST(((@PageNumber - 1)*@PageSize + 1) AS varchar(50))
/*Set filter & group variables.*/
IF @Filter IS NOT NULL AND @Filter != ''
 BEGIN
  SET @strFilter = ' WHERE ' + @Filter + ' '
  SET @strSimpleFilter = ' AND ' + @Filter + ' '
 END
ELSE
 BEGIN
  SET @strSimpleFilter = ''
  SET @strFilter = ''
 END
IF @Group IS NOT NULL AND @Group != ''
 SET @strGroup = ' GROUP BY ' + @Group + ' '
ELSE
 SET @strGroup = ''
 
/*Execute dynamic query*/ 
EXEC(
'
DECLARE @SortColumn ' + @type + '
SET ROWCOUNT ' + @strStartRow + '
SELECT @SortColumn=' + @strSortColumn + ' FROM ' + @Tables + @strFilter + ' ' +
@strGroup + ' ORDER BY ' + @Sort + '
SET ROWCOUNT ' + @strPageSize + '
SELECT ' + @Fields + ' FROM ' + @Tables + ' WHERE ' + @strSortColumn + @operator +
' @SortColumn ' + @strSimpleFilter + ' ' + @strGroup + ' ORDER BY ' + @Sort + '
'
)
GO

 
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