Question

I have a table like

ID  Name Points
1   A     10
1   A     11
1   B     11
1   B     12
1   C     12
1   C     13
2   A      8
2   A      9
2   B      9
2   B     10
2   C     10
2   C     11

I want my output to look like the following

ID   Average(A)  Average(B)  Average(C)
1     10.5          11.5         12.5
2      8.5           9.5         10.5

The following group by query displays the output but not in above format

Select Avg(Points),ID,name from table group by Name,ID

Thanks

Answer 1

Wrapping your existing query in a subquery will allow you to build out a pivot table around it. The `MAX()
aggregate’s purpose is only to eliminate the NULLs produced by the CASE statement, and therefore collapse multiple rows per ID down to one row per ID with a non-NULL in each column.

SELECT
  ID,
  MAX(CASE WHEN Name = 'A' THEN Points ELSE NULL END) AS `Average (A)`,
  MAX(CASE WHEN Name = 'B' THEN Points ELSE NULL END) AS `Average (B)`,
  MAX(CASE WHEN Name = 'C' THEN Points ELSE NULL END) AS `Average (C)`
FROM (
  SELECT ID, AVG(Points) AS Points, Name FROM yourtable GROUP BY Name, ID
) avg_subq
GROUP BY ID

Here is a live demonstration on SQLFiddle