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mysql中每组的行数

[英]Row number per group in mysql

I want to produce query result base on this scenario that can create row number according to crew_id and type.我想根据这个场景生成查询结果,可以根据crew_id和type创建行号。

id   crew_id   amount    type
 1      4       1000      AUB
 2      4       1500      AUB
 3      5       8000      CA
 4      4       1000      CA
 5      5       1000      AUB
 6      6       3000      AUB
 7      4       2000      CA
 8      6       3500      AUB
 9      4       5000      AUB
 10     5       9000      CA
 11     5       1000      CA

OUTPUT must be the ff: OUTPUT 必须是 ff:

id    crew_id   amount   type    row_number
 1      4       1000      AUB        1    
 2      4       1500      AUB        2 
 9      4       5000      AUB        3
 4      4       1000      CA         1
 7      4       2000      CA         2
 5      5       1000      AUB        1
 3      5       8000      CA         1
 10     5       9000      CA         2
 11     5       1000      CA         3
 6      6       3000      AUB        1
 6      6       3000      AUB        2

I want a single select statement only in this output我只想要这个输出中的单个 select 语句

Please go through my fiddle请通过我的小提琴

This One Last Tried最后一次尝试

    SELECT    id,
              crew_id,
              amount,
              type,
             ( 
                CASE type 
                WHEN @curType 
                THEN @curRow := @curRow + 1 
                ELSE @curRow := 1 AND @curType := type END
              ) + 1 AS rank
    FROM      Table1 p,
              (SELECT @curRow := 0, @curType := '') r
   ORDER BY  crew_id,type asc;

The question is quite old.这个问题很老了。 But I would like to post it in case someone will have a same problem.但我想发布它,以防有人遇到同样的问题。

First of all, described answers do not work correct.首先,描述的答案不正确。 For example, for例如,对于

id   crew_id   amount    type
1      4       1000      AUB
2      4       1500      AUB
5      5       1000      AUB
6      6       3000      AUB
8      6       3500      AUB
9      4       5000      AUB

(I just removed rows with type 'CA') the result table will be (我刚刚删除了类型为“CA”的行)结果表将是

id   crew_id   amount    rank   type
1      4       1000      1      AUB
2      4       1500      2      AUB
9      4       5000      3      AUB
5      5       1000      4      AUB
6      6       3000      5      AUB
8      6       3500      6      AUB

So in fact it doesn't use both crew_id and type, it just uses type.所以实际上它并没有同时使用crew_id 和type,它只使用type。

Here is how I solved this problem (probably there is a more elegant way to do it than use two nested 'CASE's, but you get the idea):这是我解决这个问题的方法(可能有一种比使用两个嵌套的“CASE”更优雅的方法,但你明白了):

SELECT id,
    amount,
    CASE crew_id 
        WHEN @curCrewId THEN
            CASE type 
                WHEN @curType THEN @curRow := @curRow + 1 
                ELSE @curRow := 1
            END
        ELSE @curRow :=1
    END AS rank,
    @curCrewId := crew_id AS crew_id,
    @curType := type AS type
FROM Table1 p
JOIN (SELECT @curRow := 0, @curCrewId := 0, @curType := '') r
ORDER BY crew_id, type

The main idea remain.主要思想仍然存在。 I just added a variable @curCrewId.我刚刚添加了一个变量@curCrewId。 If someone need to use 3 variables for grouping, so just use 3 variables and 3 nested 'CASE's.如果有人需要使用 3 个变量进行分组,那么只需使用 3 个变量和 3 个嵌套的“CASE”。 :) :)

@Janty's answer does not work when the type starts with a number (the rank starts at 2 instead of 1).当类型以数字开头(排名从 2 而不是 1 开始)时,@Janty 的答案不起作用。

Use the following instead:请改用以下内容:

SELECT id,
     crew_id,
     amount,
     CASE type 
         WHEN @curType THEN @curRow := @curRow + 1 
         ELSE @curRow := 1
     END AS rank,
     @curType := type AS type
FROM Table1 p
JOIN (SELECT @curRow := 0, @curType := '') r
ORDER BY crew_id, type

In addition to the answer of @Janty here is a solution if you want to UDATE your table with the rownumber:除了@Janty 的答案之外,如果您想使用行号对表进行 UDATE,这里还有一个解决方案:

UPDATE myTable mt,(SELECT @curRow := 0, @curType := '') r SET type=
    ( 
        CASE type 
            WHEN @curType
        THEN @curRow := @curRow + 1 
        ELSE @curRow := 1 AND @curType := type END
      )
;

As janty too crewId is not within.由于 janty 太crewId 不在其中。 Use a second "case" for that as mentioned in the other answers.如其他答案中所述,使用第二个“案例”。

With MySQL 8.0 you can use the window function ROW_NUMBER:在 MySQL 8.0 中,您可以使用窗口函数 ROW_NUMBER:

SELECT *, ROW_NUMBER() OVER(PARTITION BY crew_id) AS row_number
FROM MyTable
SELECT id, crew_id, amount, type,
       ( 
        CASE type 
          WHEN @curType 
          THEN @curRow := @curRow + 1 
          ELSE @curRow := 1 AND @curType := type  END
      ) + 1 AS rank
 FROM      Table1 p,
      (SELECT @curRow := 0, @curType := '') r
   ORDER BY  crew_id, type asc;

Here is my answer using only one case that creates row number according to both columns :这是我仅使用一种根据两列创建行号的情况的答案:

SELECT id, crew_id, amount, type,
   (CASE CONCAT(crew_id, type) 
        WHEN @cur_crew_type
        THEN @curRow := @curRow + 1
        ELSE @curRow := 0 END) + 1 AS cnt,
    @cur_crew_type := CONCAT(crew_id, type) AS cur_crew_type
FROM TABLE t,
     (SELECT @curRow := 0, @cur_crew_type := '') counter
      ORDER BY crew_id, type;

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