sql表值函数返回的变量表

Question

CREATE FUNCTION TableIncludesAlpha
(   
    @table_name nvarchar(max),
    @objectid int
)
RETURNS @table TABLE (variedTable) -- variedTable is of unknown size at function declaration
AS
BEGIN
    -- Get the SDE allocated alpha table registry
    DECLARE @tableNum nvarchar(max)
    SET @tableNum = (SELECT registration_id
                     FROM networks.sde.SDE_table_registry t
                     WHERE table_name = @table_name)

    -- Generate list of table columns, removing those we do not want
    DECLARE @cols nvarchar(max)
    SELECT @cols = STUFF((SELECT DISTINCT '], [' + name
                          FROM sys.columns
                          WHERE object_id = (SELECT TOP 1 object_id 
                                             FROM sys.objects
                                             WHERE name = 'a' + @tableNum)
                            AND name NOT IN ('SDE_STATE_ID', 'SHAPE')   -- SDE_STATE_ID doesn't exist in primary table
                          FOR XML PATH('')  -- SHAPE is the gemotery field
                         ), 1, 2, '') + ']';

    -- generate the SQL query, returns all entries from all alpha tables ordered by the ESRI timecode 'SDE_STATE_ID'
    DECLARE @query nvarchar(max) = '

    SELECT *
    FROM
        (SELECT
             a.SDE_STATE_ID as P_SDE_STATE_ID, d.*, ' + @cols + '
         FROM
             networks.networks.a' + @tableNum + ' a
         LEFT JOIN
             networks.networks.d' + @tableNum + ' d ON d.SDE_DELETES_ROW_ID = a.OBJECTID AND a.SDE_STATE_ID = d.SDE_STATE_ID
         WHERE
             ObjectID = ' + @objectid + '

         UNION

         SELECT 
             -1 as P_SDE_STATE_ID, d.*, ' + @cols + '
         FROM
             networks.networks.' + @table_name + ' a
         LEFT JOIN
             networks.networks.d' + @tableNum + ' d ON a.OBJECTID = d.SDE_DELETES_ROW_ID
         WHERE
             ObjectID = ' + @objectid + ') b
    ORDER BY 
        b.P_SDE_STATE_ID DESC'

    -- Push returns into a table that can be returned from the function
    INSERT INTO @table
        EXEC sp_executesql @query

    RETURN
END

没有，TVF无法返回未经类似的结果集。宣布表值功能的要点是，您可以知道结果表的结构并可以对其进行查询。 您可以使用其他代码或进程为您需要查询的每个输入表生成TVF，这将通过为每个表创建查询，并同时创建结构的确定性，从而为您提供结构的可变性.

我在EF迁移中使用这样的技术为每个表生成审核触发器。该代码是在一个地方定义和管理的，在SQL中，每个表都有一个实现。 如果您需要使用未构图的结果集，则应考虑存储过程，而不是功能。