Lahman's Baseball Database - Determine Primary Position - mysql

Question

I'm using Lahman's Baseball Database and MySQL to determine each player's primary position. The goal is to write a query that will return the playerID and the position at which they played most games. I know that I would probably want a query that looks something like this:
select playerID, sum(G)
from fielding
where POS = 'C'
group by playerID
order by sum(G) desc;
The above query gathers all the games each player has played as a catcher. What I want to do is take each player and compare the sum of games played at each position and find the maximum value from that.
If you are not familiar with Lahman's Baseball Database here is the download link: http://www.seanlahman.com/baseball-archive/statistics/
Also here is the create table statement for the Fielding table:
CREATE TABLE `Fielding` (
`playerID` varchar(9) NOT NULL DEFAULT '',
`yearID` int(11) NOT NULL DEFAULT '0',
`stint` int(11) NOT NULL DEFAULT '0',
`teamID` varchar(3) DEFAULT NULL,
`lgID` varchar(2) DEFAULT NULL,
`POS` varchar(2) NOT NULL DEFAULT '',
`G` int(11) DEFAULT NULL,
`GS` int(11) DEFAULT NULL,
`InnOuts` int(11) DEFAULT NULL,
`PO` int(11) DEFAULT NULL,
`A` int(11) DEFAULT NULL,
`E` int(11) DEFAULT NULL,
`DP` int(11) DEFAULT NULL,
`PB` int(11) DEFAULT NULL,
`WP` int(11) DEFAULT NULL,
`SB` int(11) DEFAULT NULL,
`CS` int(11) DEFAULT NULL,
`ZR` double DEFAULT NULL,
PRIMARY KEY (`playerID`,`yearID`,`stint`,`POS`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
The Fielding table is organized by year. POS is the position, G is for the number of games they played at the that position in the corresponding year. That means there will be multiple entires for some players in the same year. Also, ignore the case when POS = 'OF' as this takes the sum of all games played at LF, CF, and RF in the given year.
The final output should be a row for each distinct player, with columns playerID and primaryPosition.

Answer 1

plan
create table showing sums of players in all positions
get maximum sum of positions from this table
join back to sums to get the corresponding primary position
query
create table psums as
(
select playerID, POS, sum(G) as sm
from Fielding
where POS <> 'OF'
group by playerID, POS
)
;
select ps.playerID, ps.POS as primaryPosition
from
(
select playerID, max(sm) mx
from psums
group by playerID
) maxs
inner join
psums ps
on maxs.playerID = ps.playerID
and maxs.mx = ps.sm
order by ps.playerID
;
[ adding limit 10 ]
output
+-----------+-----------------+
| playerID | primaryPosition |
+-----------+-----------------+
| aardsda01 | P |
| aaronha01 | RF |
| aaronto01 | 1B |
| aasedo01 | P |
| abadan01 | 1B |
| abadfe01 | P |
| abadijo01 | 1B |
| abbated01 | 2B |
| abbeybe01 | P |
| abbeych01 | P |
+-----------+-----------------+

Answer 2

SELECT x.*
FROM fielding x
JOIN
(
SELECT playerid
, MAX(g) max_g
FROM fielding
GROUP
BY playerid
) y
ON y.playerid = x.playerid
AND y.max_g = x.g
LIMIT 10;
...or, more likely...
SELECT x.*
FROM
( SELECT playerid,pos,SUM(g) sum_g FROM fielding GROUP BY playerid,pos ) x
JOIN
(
SELECT playerid
, MAX(sum_g) max_sum_g
FROM
( SELECT playerid
, pos
, SUM(g) sum_g
FROM fielding
GROUP
BY playerid
, pos
) n
GROUP
BY playerid
) y
ON y.playerid = x.playerid
AND y.max_sum_g = x.sum_g
LIMIT 10;