如何使用MySQL组连续范围(How to group continuous ranges usin

我有一个包含类别，日期和价格表。 每个类别可以有不同的日期不同的费率，一类可以在某一特定日期只有一个速度。

Id        CatId    Date        Rate 
------  ------   ------------   ---------
000001      12   2009-07-07     1
000002      12   2009-07-08     1
000003      12   2009-07-09     1
000004      12   2009-07-10     2
000005      12   2009-07-15     1
000006      12   2009-07-16     1
000007      13   2009-07-08     1
000008      13   2009-07-09     1
000009      14   2009-07-07     2
000010      14   2009-07-08     1
000010      14   2009-07-10     1

唯一索引（CATID，日期，价格）我想每个类别组的所有连续日期范围，只保留开始和范围的结束。 对于前面的例子中，我们将有：

CatId    Begin          End            Rate 
------   ------------   ------------   ---------
12        2009-07-07    2009-07-09     1
12        2009-07-10    2009-07-10     2
12        2009-07-15    2009-07-16     1  
13        2009-07-08    2009-07-09     1  
14        2009-07-07    2009-07-07     2
14        2009-07-08    2009-07-08     1
14        2009-07-10    2009-07-10     1

我发现了一个类似的解决方案论坛 ，其并没有完全放弃的结果

WITH    q AS
        (
        SELECT  *,
                ROW_NUMBER() OVER (PARTITION BY CatId, Rate ORDER BY [Date]) AS rnd,
                ROW_NUMBER() OVER (PARTITION BY CatId ORDER BY [Date]) AS rn
        FROM    my_table
        )
SELECT  CatId AS catidd, MIN([Date]) as beginn, MAX([Date])as endd, Rate
FROM    q
GROUP BY  CatId, rnd - rn, Rate

查阅SQL FIDDLE我如何做同样的事情在MySQL？ 请帮忙！

Answer 1:

MySQL不支持分析功能，但你可以效仿这样的行为， 用户定义的变量 ：

SELECT   CatID, Begin, MAX(Date) AS End, Rate
FROM (
  SELECT   my_table.*,
           @f:=CONVERT(
             IF(@c<=>CatId AND @r<=>Rate AND DATEDIFF(Date, @d)=1, @f, Date), DATE
           ) AS Begin,
           @c:=CatId, @d:=Date, @r:=Rate
  FROM     my_table JOIN (SELECT @c:=NULL) AS init
  ORDER BY CatId, Rate, Date
) AS t
GROUP BY CatID, Begin, Rate

看到它在sqlfiddle 。

Answer 2:

SELECT catid,min(ddate),max(ddate),rate
FROM (
    SELECT
        Catid,
        Ddate,  
        rate,
        @rn := CASE WHEN (@prev <> rate 
           or DATEDIFF(ddate, @prev_date)>1) THEN @rn+1 ELSE @rn END AS rn,
        @prev := rate,
        @prev_id := catid ,
        @prev_date :=ddate
    FROM (
        SELECT CatID,Ddate,rate 
        FROM rankdate
        ORDER BY CatID, Ddate ) AS a , 
        (SELECT @prev := -1, @rn := 0, @prev_id:=0 ,@prev_date:=-1) AS vars      

) T1 group by catid,rn

注意：线（SELECT @prev：= -1，@Rn：= 0，@prev_id：= 0，@ prev_date：= - 1）AS瓦尔不是在MySQL工作区必要的，但它是在PHP的mysql_query功能。

SQL FIDDLE HERE

Answer 3:

我知道我迟到了，还是发布为我工作的解决方案。 有同样的问题，这里就是我得到了它

发现使用变量一个很好的解决方案

SELECT  MIN(id) AS id, MIN(date) AS date, MIN(state) AS state, COUNT(*) cnt
FROM    (
    SELECT  @r := @r + (@state != state OR @state IS NULL) AS gn,
            @state := state AS sn,
            s.id, s.date, s.state
    FROM    (
            SELECT  @r := 0,
                    @state := NULL
            ) vars,
            t_range s
    ORDER BY
            date, state
    ) q
GROUP BY gn

：在更多细节https://explainextended.com/2009/07/24/mysql-grouping-continuous-ranges/

文章来源: How to group continuous ranges using MySQL