题
如果我从一个月,每天,年份中从表格组中进行选择,它仅通过记录返回行,而没有任何记录的组合,使其一目了然,每天或一个月都有活动,您必须查看日期积极用于间隙的列。在 T-SQL 中,即使没有数据,如何获取每天/每月/每年的一行?
解决方案 2
我的开发者 给我回复这段代码,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。我们的示例由于连接到另一个表而有点复杂,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
其他提示
创建日历表并在该表上进行外部联接
考虑使用 数字表. 。虽然它可能很黑客,但它是我用来快速查询丢失数据、或显示所有日期或任何您想要检查某个范围内的值的内容的最佳方法,无论是否使用该范围内的所有值。
根据 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表。
http://www.sitepoint.com/forums/showthread.php?t=562806
该任务要求将一组完整的日期左连接到您的数据上,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