按DAY，MONTH，YEAR分组时sql缺少行

Question

如果我按月、日、年从表组中选择， 它只返回有记录的行，而忽略没有任何记录的组合，让人一眼就看出每天或每月都有活动，您必须积极查看日期列是否有差距。如何在 T-SQL 中获取每天/每月/每年的一行，即使没有数据存在？

Answer 1

创建一个日历表并在该表上进行外部联接

Answer 2

考虑使用numbers table。虽然它可能有点骇人听闻，但这是我用来快速查询缺失数据或显示所有日期或任何您想要检查某个范围内的值的最佳方法，无论是否使用了该范围内的所有值。

Answer 3

基于 SQLMenace 所说，您可以使用 CROSS JOIN 快速填充表或在内存中高效地创建它。
http://www.sitepoint.com/forums/showthread.php?t=562806

Answer 4

My developer 用这段代码回复了我，下划线转换为破折号，因为 StackOverflow 正在修改下划线——不需要数字表。由于连接到另一个表，我们的示例有点复杂，但也许代码示例有一天会对某人有所帮助。

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 5

该任务要求将一组完整的日期左连接到您的数据中，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