• 自己工作用过的SQL代码(1)


    SQL Server 2005下的分页SQL其实基本上有三种方法:

    1、使用SQL Server 2005中新增的ROW_NUMBER

    几种写法分别如下:

     

    1SELECT TOP 20 * FROM (SELECT
    2   ROW_NUMBER() OVER (ORDER BY Namec) AS RowNumber,
    3   *
    4FROM
    5   dbo.mem_member) _myResults
    6WHERE
    7   RowNumber > 10000
    8
     

    1SELECT * FROM (SELECT
    2   ROW_NUMBER() OVER (ORDER BY Namec) AS RowNumber,
    3   *
    4FROM
    5   dbo.mem_member) _myResults
    6WHERE
    7   RowNumber between 10000 and 10020
     

    1WITH OrderedResults AS
    2
    3(SELECT *, ROW_NUMBER() OVER (order by Namec) as RowNumber FROM dbo.mem_member)
    4
    5SELECT *
    6
    7FROM OrderedResults
    8
    9WHERE RowNumber between 10000 and 10020
    不管哪种写法,性能都不理想。在8,9万条数据的情况下要运行6秒左右。


    2、使用临时表再加存储过程

     1BEGIN
     2                DECLARE @PageLowerBound int
     3                DECLARE @PageUpperBound int
     4               
     5                -- Set the page bounds
     6                SET @PageLowerBound = 10000
     7                SET @PageUpperBound = 10020
     8
     9                -- Create a temp table to store the select results
    10                Create Table #PageIndex
    11                (
    12                    [IndexId] int IDENTITY (1, 1) NOT NULL,
    13                    [Id] varchar(18)
    14                )
    15               
    16                -- Insert into the temp table
    17                declare @SQL as nvarchar(4000)
    18                SET @SQL = 'INSERT INTO #PageIndex (Id)'
    19                SET @SQL = @SQL + ' SELECT'
    20                SET @SQL = @SQL + ' TOP ' + convert(nvarchar, @PageUpperBound)
    21                SET @SQL = @SQL + ' m_id'
    22                SET @SQL = @SQL + ' FROM dbo.mem_member'
    23                SET @SQL = @SQL + ' ORDER BY NameC'
    24               
    25                -- Populate the temp table
    26                exec sp_executesql @SQL
    27
    28                -- Return paged results
    29                SELECT O.*
    30                FROM
    31                    dbo.mem_member O,
    32                    #PageIndex PageIndex
    33                WHERE
    34                    PageIndex.IndexID > @PageLowerBound
    35                    AND O.[m_Id] = PageIndex.[Id]
    36                ORDER BY
    37                    PageIndex.IndexID
    38               
    39drop table #PageIndex           
    40                END
    而使用这种方法,在同样的情况下用时只需1秒。

    看样子,row_number是个鸡肋。

    3、如果觉得临时表不好,还可以使用SET ROWCOUNT

     1begin
     2DECLARE @first_id varchar(18), @startRow int
     3   
     4SET ROWCOUNT 10000
     5SELECT @first_id = m_id FROM mem_member ORDER BY m_id
     6
     7SET ROWCOUNT 20
     8
     9SELECT m.*
    10FROM mem_member m
    11WHERE m_id >= @first_id
    12ORDER BY m.m_id
    13
    14SET ROWCOUNT 0
    15end

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  • 原文地址:https://www.cnblogs.com/yhb199/p/1235603.html
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