MySQL - Rows to Columns and keeps NULL - mysql

Question

We have the following table (TEST2) in the MySQL database (MySQL 5.6):
TEAM_ID,MEMBER_ID,TYPE,SCORE
1,2,A,150
1,3,B,200
1,1,B,50
1,1,A,100
1,2,B,NULL
We try to transform/pivot the above table based on the TYPE column:
If the TYPE column has value == A, move the value in the SCORE column into a new column called A_SCORE. If the value in the SCORE column is NULL, it should show NULL in the new A_SCORE column.
If the TYPE column has value == B, move the value in the SCORE column into a new column called B_SCORE. If the value in the SCORE column is NULL, it should show NULL in the new B_SCORE column.
The following table is the one we are looking for (the wanted table):
TEAM_ID,MEMBER_ID,A_SCORE,B_SCORE,A_SCORE_MINUS_B_SCORE
1,1,100,50,50
1,2,150,NULL,NULL
1,3,0,200,-200
We tried the following query
SELECT TEAM_ID,MEMBER_ID,A_SCORE,B_SCORE,SUM(A_SCORE-B_SCORE) AS ACTUAL_MINUS_B_SCORE FROM
(SELECT TEAM_ID,MEMBER_ID,
CASE
WHEN SCORE IS NULL
THEN NULL
ELSE SUM(if(TYPE = 'A', SCORE,0) )
END A_SCORE,
CASE
WHEN SCORE IS NULL
THEN NULL
ELSE SUM(if(TYPE = 'B', SCORE,0) )
END B_SCORE
FROM TEST2
GROUP BY TEAM_ID,MEMBER_ID,SCORE) AS A
GROUP BY TEAM_ID,MEMBER_ID,A_SCORE,B_SCORE);
It returns something we don’t want:
TEAM_ID,MEMBER_ID,A_SCORE,B_SCORE,A_SCORE_MINUS_B_SCORE
1,1,0,50,-50
1,1,100,0,100
1,2,0,0,0
1,2,150,0,150
1,3,0,200,-200
If we tried the following, it generates a table close to what we want, but it doesn’t return any NULL value.
SELECT TEAM_ID,MEMBER_ID,A_SCORE,B_SCORE,SUM(A_SCORE-B_SCORE) AS A_SCORE _MINUS_B_SCORE FROM
(SELECT TEAM_ID,MEMBER_ID,
SUM(if(TYPE = 'A', SCORE,0) ) AS A_SCORE,
SUM(if(TYPE = 'B', SCORE,0) )AS B_SCORE
FROM TEST2
GROUP BY TEAM_ID,MEMBER_ID) AS A
GROUP BY TEAM_ID,MEMBER_ID,A_SCORE,B_SCORE;
The result of the above query:
TEAM_ID,MEMBER_ID,A_SCORE,B_SCORE,A_SCORE_MINUS_B_SCORE
1,1,100,50,50
1,2,150,0,0
1,3,0,200,-200
Could any guru enlighten how to generate the wanted table in this case using MySQL? The SQL fiddle is here for your convenience.
http://sqlfiddle.com/#!9/cfe7a1/1
Thanks!

Answer 1

Try this;)
SELECT TEAM_ID, MEMBER_ID, A_SCORE, B_SCORE, A_SCORE - B_SCORE AS A_SCORE_MINUS_B_SCORE
FROM (
SELECT
TEAM_ID, MEMBER_ID,
CASE
WHEN A_SCORE IS NULL AND NOT EXISTS (
SELECT 1 FROM TEST2
WHERE TEAM_ID = T1.TEAM_ID
AND MEMBER_ID = T1.MEMBER_ID
AND TYPE = 'A'
) THEN 0 ELSE A_SCORE END AS A_SCORE,
CASE
WHEN B_SCORE IS NULL AND NOT EXISTS (
SELECT 1 FROM TEST2
WHERE TEAM_ID = T1.TEAM_ID
AND MEMBER_ID = T1.MEMBER_ID
AND TYPE = 'A'
) THEN 0 ELSE B_SCORE END AS B_SCORE
FROM (
SELECT
TEAM_ID, MEMBER_ID,
MAX(CASE WHEN TYPE = 'A' THEN SCORE END) AS A_SCORE,
MAX(CASE WHEN TYPE = 'B' THEN SCORE END) AS B_SCORE
FROM TEST2
GROUP BY TEAM_ID, MEMBER_ID
) T1
)T
SQLFiddle demo here

Answer 2

I don't quite understand the calculation criteria, but something like this should work...
SELECT team_id
, member_id
, COALESCE(MAX(CASE WHEN type = 'A' THEN score END),0) a_score
, COALESCE(MAX(CASE WHEN type = 'B' THEN score END),0) b_score
, COALESCE(MAX(CASE WHEN type = 'A' THEN score END),0)
- COALESCE(MAX(CASE WHEN type = 'B' THEN score END),0) diff
FROM test2
GROUP
BY team_id
, member_id;