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我有一张表格，其中包含来自旅行社的所有预订和用户数据，并想了解以下内容：

Traveler 可以在表中有多个记录 Traveler 由 dedup 列标识

我想知道每年的每个月，有多少人在那个月旅行过，前一年旅行过（我怎样才能找到前一年旅行过的给定月份和年份的旅行者人数)

是否有可能有一个类似的结果表，其中包含一个额外的列，其中包含前一年经过的记录数？

我是 SQL 的新手，但渴望学习并且已经尝试了 2 天，仅使用此查询来计算每个月和每年的所有唯一旅行者：

SELECT BookingYear, BookingMonth, COUNT( DISTINCT (Dedup) ) 
AS  'Count of travellers'
FROM DATA
GROUP BY BookingYear, BookingMonth

产生这个数据集：

+-------------+--------------+---------------------+
| BookingYear | BookingMonth | Count of travellers |
+-------------+--------------+---------------------+
|        2009 |           11 |                 384 |
|        2009 |           12 |                1084 |
|        2010 |            1 |                4641 |
|        2010 |            2 |                1922 |
|        2010 |            3 |                1453 |
|        2010 |            4 |                1032 |
|        2010 |            5 |                 967 |
|        2010 |            6 |                1095 |
|        2010 |            7 |                2490 |
|        2010 |            8 |                2425 |
|        2010 |            9 |                 920 |
|        2010 |           10 |                 213 |
|        2010 |           11 |                1140 |
|        2010 |           12 |                1981 |
|        2011 |            1 |                3514 |
|        2011 |            2 |                1284 |
|        2011 |            3 |                1424 |
|        2011 |            4 |                 867 |
|        2011 |            5 |                1395 |
|        2011 |            6 |                1318 |
|        2011 |            7 |                3182 |
|        2011 |            8 |                2491 |
|        2011 |            9 |                1119 |
|        2011 |           10 |                 144 |
|        2011 |           11 |                1937 |
|        2011 |           12 |                3092 |
|        2012 |            1 |                4752 |
|        2012 |            2 |                1266 |
|        2012 |            3 |                 949 |
|        2012 |            4 |                1107 |
|        2012 |            5 |                1352 |
|        2012 |            6 |                1454 |
|        2012 |            7 |                3365 |
|        2012 |            8 |                1590 |
|        2012 |            9 |                 656 |
|        2012 |           10 |                 209 |
|        2012 |           11 |                2445 |
|        2012 |           12 |                3769 |
|        2013 |            1 |                7570 |
|        2013 |            2 |                4646 |
|        2013 |            3 |                2329 |
|        2013 |            4 |                2666 |
|        2013 |            5 |                2506 |
|        2013 |            6 |                1973 |
|        2013 |            7 |                3336 |
|        2013 |            8 |                2229 |
|        2013 |            9 |                 398 |
+-------------+--------------+---------------------+

这是表结构：

+----------------------+---------------+------+-----+---------+-------+
| Field                | Type          | Null | Key | Default | Extra |
+----------------------+---------------+------+-----+---------+-------+
| BookingCode          | int(15)       | YES  |     | NULL    |       |
| Dedup                | varchar(50)   | YES  |     | NULL    |       |
| BookToDep            | int(4)        | YES  |     | NULL    |       |
| BookingYear          | int(4)        | YES  |     | NULL    |       |
| BookingMonth         | int(2)        | YES  |     | NULL    |       |
| DepartureYear        | int(4)        | YES  |     | NULL    |       |
| DepartureMonth       | int(2)        | YES  |     | NULL    |       |
| GroupCount           | int(3)        | YES  |     | NULL    |       |
| Duration             | int(3)        | YES  |     | NULL    |       |
| Gender               | varchar(10)   | YES  |     | NULL    |       |
| Age                  | int(3)        | YES  |     | NULL    |       |
| Birthdate            | datetime      | YES  |     | NULL    |       |
| Country              | varchar(2)    | YES  |     | NULL    |       |
| AccoCountry          | varchar(50)   | YES  |     | NULL    |       |
| AccoRegion           | varchar(50)   | YES  |     | NULL    |       |
| AccoDestination      | varchar(50)   | YES  |     | NULL    |       |
| RevenueEntireBooking | decimal(15,2) | YES  |     | NULL    |       |
+----------------------+---------------+------+-----+---------+-------+

这是数据的摘录：

+-------------+-------------------------+-----------+-------------+--------------+---------------+----------------+------------+----------+--------+------+---------------------+---------+-------------+-----------------+-----------------+----------------------+
| BookingCode | Dedup                   | BookToDep | BookingYear | BookingMonth | DepartureYear | DepartureMonth | GroupCount | Duration | Gender | Age  | Birthdate           | Country | AccoCountry | AccoRegion      | AccoDestination | RevenueEntireBooking |
+-------------+-------------------------+-----------+-------------+--------------+---------------+----------------+------------+----------+--------+------+---------------------+---------+-------------+-----------------+-----------------+----------------------+
|      948757 | EMMENROCUS14390         |       188 |        2009 |           11 |          2010 |              5 |          7 |        8 | M      |   73 | 1939-05-25 00:00:00 | NL      | Turkije     | Turkse  Riviera | Lara            |              4136.00 |
|      948757 | EMMENANTONETTA28626     |       188 |        2009 |           11 |          2010 |              5 |          7 |        8 | F      |   34 | 1978-05-16 00:00:00 | NL      | Turkije     | Turkse  Riviera | Lara            |              4136.00 |
|      948757 | HEESTERSWESLEY34719     |       188 |        2009 |           11 |          2010 |              5 |          7 |        8 | M      |   17 | 1995-01-20 00:00:00 | NL      | Turkije     | Turkse  Riviera | Lara            |              4136.00 |
|      948757 | EMMENHUBERDINA25710     |       188 |        2009 |           11 |          2010 |              5 |          7 |        8 | F      |   42 | 1970-05-22 00:00:00 | NL      | Turkije     | Turkse  Riviera | Lara            |              4136.00 |
|      948757 | HEESTERSANTHONY25917    |       188 |        2009 |           11 |          2010 |              5 |          7 |        8 | M      |   41 | 1970-12-15 00:00:00 | NL      | Turkije     | Turkse  Riviera | Lara            |              4136.00 |
|      948757 | VANDERHOEVENRONALD27069 |       188 |        2009 |           11 |          2010 |              5 |          7 |        8 | M      |   38 | 1974-02-09 00:00:00 | NL      | Turkije     | Turkse  Riviera | Lara            |              4136.00 |
|      948757 | HEESTERSMIRTHE35781     |       188 |        2009 |           11 |          2010 |              5 |          7 |        8 | C      |   14 | 1997-12-17 00:00:00 | NL      | Turkije     | Turkse  Riviera | Lara            |              4136.00 |
|      949055 | BOGERSPATRICK26350      |       184 |        2009 |           11 |          2010 |              5 |          4 |       11 | M      |   40 | 1972-02-21 00:00:00 | NL      | Turkije     | Turkse  Riviera | Belek           |              1922.00 |
|      949055 | BOGERSJORDI37246        |       184 |        2009 |           11 |          2010 |              5 |          4 |       11 | C      |   10 | 2001-12-21 00:00:00 | NL      | Turkije     | Turkse  Riviera | Belek           |              1922.00 |
|      949055 | DEBREEESTHER25664       |       184 |        2009 |           11 |          2010 |              5 |          4 |       11 | F      |   42 | 1970-04-06 00:00:00 | NL      | Turkije     | Turkse  Riviera | Belek           |              1922.00 |
+-------------+-------------------------+-----------+-------------+--------------+---------------+----------------+------------+----------+--------+------+---------------------+---------+-------------+-----------------+-----------------+----------------------+
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1 回答 1

0

如果您使用的是 SQL Server：

with cte as (
    select 
       d.BookingYear, d.BookingMonth, count(distinct(d.Dedup)) as [Count of travellers]
    from DATA as d
    group by d.BookingYear, d.BookingMonth
)
select
    c.BookingYear, c.BookingMonth,
    c.[Count of travellers],
    isnull(c2.[Count of travellers], 0) as [Count of travellers previous year]
from cte as c
    left outer join cte as c2 on
        c2.BookingMonth = c.BookingMonth and c2.BookingYear = c1.BookingYear - 1

对于 MySQL，您可以使用：

    select 
        d.BookingYear, d.BookingMonth,
        count(distinct(d.Dedup)) as [Count of travellers],
        count(distinct(d2.Dedup)) as [Count of travellers previous year]
    from DATA as d
        left outer join DATA as d2 on 
           d2.BookingMonth = d.BookingMonth and d2.BookingYear = d1.BookingYear - 1
    group by d.BookingYear, d.BookingMonth
于 2013-09-14T17:00:03.410 回答