SQL日期查询即使没有数据也包含月份 [英] SQL Date Query include month even if no data
问题描述
我有一个预订数据库,其中包含每个预订的不同日期。我想获得每月所有预订的计数,例如
I have a booking database with various dates for each booking. I want to get a count of all bookings in each month e.g.
JAN | 12
FEB | 15
MAR | 53
APR | 25
如果一个月内的预订量为零,如何仍能列出该月份?例如:
If I have zero bookings in a month, how can I still get the month listed? e.g.:
JAN | 12
FEB | 15
MAR | 53
APR | 0
MAY | 52
图式:
ID | BookingDate | REF
我没有或不想参加一个月的会议。
I don't have or want to have a months table to join against.
以下是我到目前为止的查询:
Below is my query so far:
SELECT TOP 1000 [Id]
,[MemberId]
,[LocationId]
,[Date]
,[BookingStateId]
,[RPEFeeling]
,[RPEPush]
,[Notes]
,[TimeSlotId]
,[MembershipId]
,[TrialSession]
,[CreatedDate]
,[ModifiedDate]
,[CreatedBy]
,[ModifiedBy]
FROM [DB].[dbo].[SessionBooking]
DECLARE @months TABLE (MonthNumber INT, YearNumber INT, Name VARCHAR(50))
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (1, 2014, 'Jan')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (2, 2014, 'Feb')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (3, 2014, 'Mar')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (4, 2014, 'Apr')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (5, 2014, 'May')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (6, 2014, 'Jun')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (7, 2014, 'Jul')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (8, 2014, 'Aug')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (9, 2014, 'Sept')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (10, 2014, 'Oct')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (11, 2014, 'Nov')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (12, 2014, 'Dec')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (1, 2015, 'Jan')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (2, 2015, 'Feb')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (3, 2015, 'Mar')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (4, 2015, 'Apr')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (5, 2015, 'May')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (6, 2015, 'Jun')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (7, 2015, 'Jul')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (8, 2015, 'Aug')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (9, 2015, 'Sept')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (10, 2015, 'Oct')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (11, 2015, 'Nov')
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (12, 2015, 'Dec')
SELECT MonthNumber, YearNumber, SUM(Id)
FROM SessionBooking b
RIGHT JOIN @months mo ON DATEPART(m, b.Date) = mo.MonthNumber
AND DATEPART(yy, b.Date) = mo.YearNumber
GROUP BY mo.MonthNumber, mo.YearNumber
这仅返回以下结果(过去两个月中每个月有多次预订。
This is only returning the following results (where there are multiple bookings over last two years on each month.
MonthNumber YearNumber (No column name)
1 2014 NULL
2 2014 NULL
3 2014 NULL
4 2014 NULL
5 2014 NULL
6 2014 NULL
7 2014 NULL
8 2014 NULL
9 2014 NULL
10 2014 NULL
11 2014 NULL
12 2014 NULL
1 2015 NULL
2 2015 215
3 2015 134
4 2015 NULL
5 2015 NULL
6 2015 NULL
7 2015 NULL
8 2015 NULL
9 2015 NULL
10 2015 NULL
11 2015 NULL
12 2015 NULL
推荐答案
您需要拥有所有月份的表变量并进行JOIN。
You need to have a table variable with all the months and do a JOIN.
DECLARE @months TABLE (MonthNumber INT, YearNumber INT, Name VARCHAR(50))
INSERT INTO @months (MonthNumber, YearNumber, Name) VALUES (1, 2015, 'January')
...
SELECT MonthNumber, YearNumber, ISNULL(SUM(...), 0)
FROM Booking b
RIGHT JOIN @months mo ON DATEPART(m, b.BookingDate)=mo.MonthNumber AND DATEPART(yy, b.BookingDate)=mo.YearNumber
GROUP BY mo.MonthNumber, mo.YearNumber
编辑:如果要考虑多年,请将Year添加为@month列,并更改CROSS JOIN条件以考虑月份和年份。
If you want to consider multiple years, add year as a column in @month and change the CROSS JOIN condition to consider month and year.
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