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Hello, hope someone can help me out here


I have a table,



Table Scores




First I want to join the rows on ID when the score is the same, so that in the example below ID 2 has one row.




But is it also possible to remove the score column and put the score in the different year-columns as below?



Thank you

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The year1, year2, year3 columns smell like an error in the design, repeating columns are usually not as flexible as you might want.


Your first question could be a simple as running an aggregate:

SELECT id, SUM(year1), SUM(year2), ... FROM table GROUP BY id;


The second question requires more rules, you have put A and C in the same row, and all the B's in the second, why can A and C be merged, but the B in year-2 cannnot?

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The first table is an example how I worked it out..so per score there is a row now ...now I want to bring it back per ID and that worked with what you explained

 SELECT id, SUM(year1), SUM(year2), ... FROM table GROUP BY id

and when I write

SUM(year1)>0 year1

it gives the scores per ID in each column.

Now I like to see the different scores in one row but I guess it's won't work out

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  • Solution

This is screaming for normalization, but this will work (link to http://sqlfiddle.com/#!2/30c2b/1/0):

select id
, IFNULL(group_concat(year1),0) as `Year 1`
, IFNULL(group_concat(year2),0) as `Year 2`
, IFNULL(group_concat(year3),0) as `Year 3`
from (
select id
, IF(year1,score,null) as year1
, IF(year2,score,null) as year2
, IF(year3,score,null) as year3
from scores
) t1
group by id;

Obviously, depending on how you want duplicates and sorting, you'll need to tweak the group_concat() call slightly.

Edited by fenway
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