I have a table:
我有一个表:
id | value
1 | -
1 | a
2 | b
1 | c
3 | d
2 | e
then I need a counter column which begins from 1 for every different value in the id column
然后我需要一个计数器列,它从1开始,针对id列中的每个不同值
Desired select result:
想要选择结果:
id | value | counter
1 | - | 1
1 | a | 2
2 | b | 1
1 | c | 3
3 | d | 1
2 | e | 2
All I found was for counting the number of duplicates etc., but not for an incrementing counter on each duplicate of a specific column...?
我所发现的只是计算重复的次数等等,而不是对特定列的每一个重复的递增计数器…?
4 个解决方案
#1
6
If you do not care about ordering, only about corresponding row number, use variables like this:
如果你不关心排序,只关心对应的行号,使用如下变量:
SELECT
t.*,
@i:=IF(id=@id, @i+1, 1) AS num,
@id:=id
FROM
t
CROSS JOIN (SELECT @i:=0, @id:=0) AS init
ORDER BY id
#2
1
What you are trying to accomplish is called RANKING . Unfortunately MySQL doesnot have ranking functions like in SQL Server ROW_NUMBER()
, DENSE_RANK()
etc..
你想要达到的目标叫做排名。不幸的是,MySQL没有像SQL Server ROW_NUMBER()、DENSE_RANK()这样的排序函数。
You can try below query for MySQL
你可以试试下面的MySQL查询。
SELECT t.ID, t.Value, count(*) as Counter
FROM tableName t
JOIN tableName b ON t.ID = b.ID AND t.Value >= b.Value
GROUP BY t.ID, t.Value
SQL小提琴演示
#3
0
select t.id1, t.value,
row_number() over (partition by t.id1 order by t.value ) counter
from test t;
I hope this will be useful:)
我希望这将是有用的:
#4
0
This will do the work for you:
这对你有帮助:
SELECT [id]
,[value]
,ROW_NUMBER() OVER (PARTITION BY [id] ORDER BY value) AS 'counter'
FROM [TableName]
ROW_NUMBER will add the numbering. The PARTITION BY clause allows us to group the results within the call to ROW_NUMBER() without grouping them ourselves via a GROUP BY. It just tells the ROW_NUMBERR what groupings to use when it does its counting.
ROW_NUMBER将添加编号。通过PARTITION BY子句,我们可以在对ROW_NUMBER()的调用中对结果进行分组,而不必自己通过group BY对它们进行分组。它只告诉ROW_NUMBERR在计数时使用什么组。
For MySql you can use those links:
对于MySql,您可以使用以下链接:
http://blog.sqlauthority.com/2014/03/09/mysql-reset-row-number-for-each-group-partition-by-row-number/
http://www.folkstalk.com/2013/03/grouped-row-number-function-mysql.html
http://www.folkstalk.com/2013/03/grouped-row-number-function-mysql.html
In your case:
在你的例子:
SET @row_number:=0;
SET @id:='';
SELECT @row_number:=CASE WHEN @id=id THEN @row_number+1 ELSE 1 END AS row_number , @id:=id AS id, value
FROM TableName
ORDER BY id;
#1
6
If you do not care about ordering, only about corresponding row number, use variables like this:
如果你不关心排序,只关心对应的行号,使用如下变量:
SELECT
t.*,
@i:=IF(id=@id, @i+1, 1) AS num,
@id:=id
FROM
t
CROSS JOIN (SELECT @i:=0, @id:=0) AS init
ORDER BY id
#2
1
What you are trying to accomplish is called RANKING . Unfortunately MySQL doesnot have ranking functions like in SQL Server ROW_NUMBER()
, DENSE_RANK()
etc..
你想要达到的目标叫做排名。不幸的是,MySQL没有像SQL Server ROW_NUMBER()、DENSE_RANK()这样的排序函数。
You can try below query for MySQL
你可以试试下面的MySQL查询。
SELECT t.ID, t.Value, count(*) as Counter
FROM tableName t
JOIN tableName b ON t.ID = b.ID AND t.Value >= b.Value
GROUP BY t.ID, t.Value
SQL小提琴演示
#3
0
select t.id1, t.value,
row_number() over (partition by t.id1 order by t.value ) counter
from test t;
I hope this will be useful:)
我希望这将是有用的:
#4
0
This will do the work for you:
这对你有帮助:
SELECT [id]
,[value]
,ROW_NUMBER() OVER (PARTITION BY [id] ORDER BY value) AS 'counter'
FROM [TableName]
ROW_NUMBER will add the numbering. The PARTITION BY clause allows us to group the results within the call to ROW_NUMBER() without grouping them ourselves via a GROUP BY. It just tells the ROW_NUMBERR what groupings to use when it does its counting.
ROW_NUMBER将添加编号。通过PARTITION BY子句,我们可以在对ROW_NUMBER()的调用中对结果进行分组,而不必自己通过group BY对它们进行分组。它只告诉ROW_NUMBERR在计数时使用什么组。
For MySql you can use those links:
对于MySql,您可以使用以下链接:
http://blog.sqlauthority.com/2014/03/09/mysql-reset-row-number-for-each-group-partition-by-row-number/
http://www.folkstalk.com/2013/03/grouped-row-number-function-mysql.html
http://www.folkstalk.com/2013/03/grouped-row-number-function-mysql.html
In your case:
在你的例子:
SET @row_number:=0;
SET @id:='';
SELECT @row_number:=CASE WHEN @id=id THEN @row_number+1 ELSE 1 END AS row_number , @id:=id AS id, value
FROM TableName
ORDER BY id;