吉日分页转载

-- =============================================
-- Author: 吉日嘎拉
-- Create date: 2012年02月23日
-- Description: 2012年02月23日编码规范化
-- =============================================
ALTER PROCEDURE [dbo].[GetRecordByPage]
@TableName VARCHAR(4000), -- 表名
@SelectField VARCHAR(4000), -- 要显示的字段名(不要加select)
@WhereConditional VARCHAR(4000), -- 查询条件(注意: 不要加 where)
@SortExpression VARCHAR(255), -- 排序索引字段名
@PageSize INT = 20, -- 页大小
@PageIndex INT = 1, -- 页码
@RecordCount INT OUTPUT, -- 返回记录总数
@SortDire VARCHAR(5) = 'DESC' -- 设置排序类型, 非 0 值则降序
AS
BEGIN

DECLARE @commandText VARCHAR(8000)      -- 主语句
DECLARE @TopN INT                         -- 获取前几条记录
DECLARE @PageCount INT                     -- 总共会是几页
DECLARE @TopLimit INT                     -- 获取多少条记录
DECLARE @SQLRowCount NVARCHAR(4000)     -- 用于查询记录总数的语句
DECLARE @SQLOrder VARCHAR(400)          -- 排序类型
DECLARE @SQLTemp VARCHAR(4000)          -- 临时变量

SET @SortExpression = LTRIM(RTRIM(@SortExpression))
SET @SortDire = UPPER(LTRIM(RTRIM(@SortDire)))

-- 这里是计算整体记录行数
IF @RecordCount IS NULL
BEGIN
    IF @WhereConditional != ''
    BEGIN
      SET @SQLRowCount = 'SELECT @RecordCount=COUNT(1) FROM ' + @TableName + ' WHERE ' + @WhereConditional
    END
    ELSE
    BEGIN
      SET @SQLRowCount = 'SELECT @RecordCount=COUNT(1) FROM ' + @TableName
    END
END

-- SELECT @RecordCount=@@ROWCOUNT
EXEC sp_executesql @SQLRowCount, N'@RecordCount INT OUT', @RecordCount out

IF @RecordCount IS NULL
BEGIN
   SET @RecordCount = 0
END

-- 这里是控制页数最多少
SET @PageCount = @RecordCount / @PageSize + 1

-- 这里检查当前页的有效性
IF (@PageIndex < 1)
BEGIN
    SET @PageIndex = 1
END

-- 这里限制最后一页的有效性
IF (@PageIndex > @PageCount)
BEGIN
    SET @PageIndex = @PageCount
END

IF @SortDire != 'ASC'
BEGIN
    SET @SQLTemp = '<(SELECT MIN'
    SET @SQLOrder = ' ORDER BY ' + @SortExpression + ' DESC'
END
ELSE
BEGIN
    set @SQLTemp = '>(SELECT MAX'
    set @SQLOrder = ' ORDER BY ' + @SortExpression + ' ASC'
END

-- 这里是调试信息
-- SELECT @SQLOrder

-- 获取几条数据？ 吉日嘎拉 2010-11-02 更新
SET @TopN = @RecordCount - @PageSize * (@PageIndex - 1)
IF @TopN > @PageSize
BEGIN
    SET @TopN = @PageSize
END

SET @TopLimit = @PageSize * (@PageIndex - 1)
IF @TopLimit > @RecordCount
BEGIN
    SET @TopLimit = @RecordCount
END

SET @commandText = 'SELECT TOP ' + STR(@TopN) + ' ' + @SelectField + ' FROM '
    + @TableName + ' WHERE ' + @SortExpression + @SQLTemp + '('
    + RIGHT(@SortExpression, LEN(@SortExpression) - CHARINDEX('.', @SortExpression)) + ') FROM (SELECT TOP ' + STR(@TopLimit)
    + ' ' + @SortExpression + ' FROM ' + @TableName  + @SQLOrder + ') AS TableTemp)'
    + @SQLOrder

IF @WhereConditional != ''
    SET @commandText = 'SELECT TOP ' + STR(@TopN) + ' ' + @SelectField + ' FROM '
        + @TableName + ' WHERE ' + @SortExpression + @SQLTemp + '('
        + RIGHT(@SortExpression, LEN(@SortExpression) - CHARINDEX('.',@SortExpression)) + ') FROM (SELECT TOP ' + STR(@TopLimit)
        + ' ' + @SortExpression + ' FROM ' + @TableName + ' WHERE ' + @WhereConditional + ' '
        + @SQLOrder + ') AS TableTemp) AND ' + @WhereConditional + ' ' + @SQLOrder

IF @PageIndex = 1
BEGIN
    -- 第一页的显示效率提高
    SET @SQLTemp = ''
    IF @WhereConditional != ''
        SET @SQLTemp = ' WHERE ' + @WhereConditional

    SET @commandText = 'SELECT TOP ' + STR(@TopN) + ' ' + @SelectField 
                      + ' FROM ' + @TableName + @SQLTemp + ' ' + @SQLOrder
END
ELSE
BEGIN    
    -- 解决大数据最有一页卡死的问题
    IF @PageIndex = @PageCount
    BEGIN
        IF @SortDire = 'ASC'
        BEGIN
            SET @SQLOrder = ' ORDER BY ' + @SortExpression + ' DESC'
        END
        ELSE
        BEGIN
            SET @SQLOrder = ' ORDER BY ' + @SortExpression + ' ASC'
        END
    
        SET @SQLTemp = ''
        IF @WhereConditional != ''
            SET @SQLTemp = ' WHERE ' + @WhereConditional
            
        SET @commandText = 'SELECT TOP ' + STR(@TopN) + ' ' + @SelectField 
                          + ' FROM ' + @TableName + @SQLTemp + ' ' + @SQLOrder
        
        SET @commandText = 'SELECT ' + @SelectField
                          + ' FROM (' + @commandText + ') AS TableTemp ORDER BY ' + @SortExpression + ' ' + @SortDire
    END
END

EXEC (@commandText)

-- 这个是调试程序用的
-- SELECT @commandText

END