Question

我有以下SQL函数定义和测试：

IF EXISTS (SELECT *
       FROM   sys.objects
       WHERE  object_id = OBJECT_ID(N'[dbo].[udf_Assessment_Timelines]')
              AND type IN ( N'FN', N'IF', N'TF', N'FS', N'FT' ))
  DROP FUNCTION [dbo].udf_Assessment_Timelines
GO 
CREATE FUNCTION dbo.udf_Assessment_Timelines
(
    @startDate datetime, 
    @endDate datetime,
    @assessmentId int = 14,
    @outIds nvarchar(max)='3,9,10'
)
RETURNS @result TABLE(case_id int, [TOTAL DAYS] int)
AS
BEGIN
    DECLARE @in TimeLineReportList;
    DECLARE @out TimeLineReportList;

    INSERT INTO @in
       SELECT * FROM dbo.udf_First_Timeline_Entries_Of_Status(@assessmentId)

    INSERT INTO @out
       SELECT * FROM dbo.udf_First_Timeline_Entries_Of_Any_Statuses(@outIds)

    INSERT INTO @result
        SELECT * FROM dbo.udf_Generic_Timelines(@startDate, @endDate, @in, @out,null)

    RETURN
END
GO

SELECT * FROM dbo.udf_Assessment_Timelines('2013-01-01T00:00:00.000', '2014-01-01T00:00:00.000',null,null)

调用该函数的最后一行返回0行。但是，下面的SQL直接执行时会返回行。有什么区别？

DECLARE @result TABLE(case_id int, [TOTAL DAYS] int)    
DECLARE @in TimeLineReportList;
DECLARE @out TimeLineReportList;

INSERT INTO @in
   SELECT * FROM dbo.udf_First_Timeline_Entries_Of_Status(14)

INSERT INTO @out
   SELECT * FROM dbo.udf_First_Timeline_Entries_Of_Any_Statuses('3,9,10')

INSERT INTO @result
    SELECT * FROM dbo.udf_Generic_Timelines('2013-01-01T00:00:00.000', '2014-01-01T00:00:00.000', @in, @out,null)

SELECT * FROM @result

Answer 1

您在不起作用的版本中覆盖@assessmentId和@outIds为null。

SELECT * FROM dbo.udf_Assessment_Timelines('2013-01-01T00:00:00.000', 
    '2014-01-01T00:00:00.000', null, null)
                               ^     ^

如果您想使用这些参数的默认值，请改为使用default关键字：

SELECT * FROM dbo.udf_Assessment_Timelines('2013-01-01T00:00:00.000', 
    '2014-01-01T00:00:00.000', default, default)
                               ^        ^

SQL函数不返回任何结果，但函数内容返回结果

1 个答案: