按DAY，MONTH，YEAR分组时，sql缺少行

Question

如果我按月，日，年从表格组中选择， 它只返回带有记录的行，并且没有任何记录就会留下组合，使得它看起来每天或每月都有活动，您必须主动查看日期列以查找差距。如何在T-SQL中获取每天/每月/每年的行，即使没有数据？

Answer 1

在该表上创建日历表和外部联接

Answer 2

My developer使用此代码返回给我，下划线转换为破折号，因为StackOverflow正在破坏下划线 - 不需要数字表。我们的例子通过连接到另一个表有点复杂，但也许代码示例有一天会帮助某人。

declare @career-fair-id int 
select @career-fair-id = 125

create table #data ([date] datetime null, [cumulative] int null) 

declare @event-date datetime, @current-process-date datetime, @day-count int 
select @event-date = (select careerfairdate from tbl-career-fair where careerfairid = @career-fair-id) 
select @current-process-date = dateadd(day, -90, @event-date) 

    while @event-date <> @current-process-date 
    begin 
    select @current-process-date = dateadd(day, 1, @current-process-date) 
    select @day-count = (select count(*) from tbl-career-fair-junction where attendanceregister <= @current-process-date and careerfairid = @career-fair-id) 
        if @current-process-date <= getdate() 
        insert into #data ([date], [cumulative]) values(@current-process-date, @day-count) 
    end 

    select * from #data 
    drop table #data 

Answer 3

考虑使用numbers table。虽然它可能是hackish，但它是我快速查询缺失数据，显示所有日期或任何你想要检查范围内的值的方法，而不管是否使用该范围内的所有值。 / p>

Answer 4

在SQLMenace所说的基础上，您可以使用CROSS JOIN快速填充表格或在内存中高效创建它。
http://www.sitepoint.com/forums/showthread.php?t=562806

Answer 5

该任务要求将一整套日期保留在您的数据上，例如


DECLARE @StartInt int
DECLARE @Increment int
DECLARE @Iterations int

SET @StartInt = 0
SET @Increment = 1
SET @Iterations = 365


SELECT
    tCompleteDateSet.[Date]
  ,AggregatedMeasure = SUM(ISNULL(t.Data, 0))
FROM
        (

            SELECT
                [Date] = dateadd(dd,GeneratedInt, @StartDate)
            FROM
                [dbo].[tvfUtilGenerateIntegerList] (
                        @StartInt,
                        ,@Increment,
                        ,@Iterations
                    )
            ) tCompleteDateSet
    LEFT JOIN tblData t
          ON (t.[Date] = tCompleteDateSet.[Date])
GROUP BY
tCompleteDateSet.[Date]

其中表值函数tvfUtilGenerateIntegerList定义为


-- Example Inputs

-- DECLARE @StartInt int
-- DECLARE @Increment int
-- DECLARE @Iterations int
-- SET @StartInt = 56200
-- SET @Increment = 1
-- SET @Iterations = 400
-- DECLARE @tblResults TABLE
-- (
--     IterationId int identity(1,1),
--     GeneratedInt int
-- )


-- =============================================
-- Author: 6eorge Jetson
-- Create date: 11/22/3333
-- Description: Generates and returns the desired list of integers as a table
-- =============================================
CREATE FUNCTION [dbo].[tvfUtilGenerateIntegerList]
(
    @StartInt int,
    @Increment int,
  @Iterations int
)
RETURNS
@tblResults TABLE
(
    IterationId int identity(1,1),
    GeneratedInt int
)
AS
BEGIN

  DECLARE @counter int
  SET @counter= 0
  WHILE (@counter < @Iterations)
    BEGIN
    INSERT @tblResults(GeneratedInt) VALUES(@StartInt + @counter*@Increment)
    SET @counter = @counter + 1
    END


  RETURN
END
--Debug
--SELECT * FROM @tblResults