Only show the highest amount on an INNER JOIN - mysql

Question

We have an interactive Map of America which shows the state which equals your requirement.
We have an Problem with our Database, we have two tables staaten and economydata.
Our inner join
SELECT staaten.staat_id, staat_name, economydata.INDUSTRY_ID, economydata.INDUSTRIE_UMSATZ_ANTEIL
FROM staaten, economydata
WHERE staaten.staat_id = economydata.staat_i;`
gives us this output:
staat_id staat_name INDUSTRY_ID INDUSTRIE_UMSATZ_ANTEIL
1 Alabama 3 1
1 Alabama 6 1
1 Alabama 10 3
1 Alabama 11 4
1 Alabama 12 18
1 Alabama 13 11
1 Alabama 25 7
1 Alabama 34 6
1 Alabama 35 7
1 Alabama 36 3
1 Alabama 45 2
1 Alabama 51 5
1 Alabama 56 11
1 Alabama 60 6
1 Alabama 64 1
1 Alabama 65 3
1 Alabama 69 1
1 Alabama 70 7
1 Alabama 75 0
1 Alabama 78 3
1 Alabama 81 3
1 Alabama 82 17
2 Alaska 3 2
2 Alaska 6 16
2 Alaska 10 2
2 Alaska 11 4
2 Alaska 12 3
2 Alaska 13 0
2 Alaska 25 3
2 Alaska 34 2
2 Alaska 35 4
2 Alaska 36 12
2 Alaska 45 3
2 Alaska 51 3
2 Alaska 56 9
2 Alaska 60 4
2 Alaska 64 1
2 Alaska 65 2
2 Alaska 69 0
2 Alaska 70 7
2 Alaska 75 1
2 Alaska 78 3
2 Alaska 81 2
2 Alaska 82 21
But we only need one row per Staate which only contains the Highest economydata.INDUSTRIE_UMSATZ_ANTEIL with the INDUSTRY_ID.
The closest we got was with SELECT ... MAX(economydata.INDUSTRIE_UMSATZ_ANTEIL) FROM ... GROUP BY staaten.staat_name but we lost the connection between economydata.INDUSTRIE_UMSATZ_ANTEIL and INDUSTRY_ID, it showed us the Highest INDUSTRIE_UMSATZ_ANTEIL but not the right INDUSTRY_ID

Answer 1

You could use a tuple and a in clause on the result for max(INDUSTRIE_UMSATZ_ANTEIL) group by staat_id
SELECT
staaten.staat_id
, staat_name
, economydata.INDUSTRY_ID
, economydata.INDUSTRIE_UMSATZ_ANTEIL
FROM staaten
INNER JOIN economydata on staaten.staat_id = economydata.staat_i
where (staaten.staat_id, economydata.INDUSTRIE_UMSATZ_ANTEIL ) in (
SELECT
staaten.staat_id
, max(economydata.INDUSTRIE_UMSATZ_ANTEIL)
FROM staaten
INNER JOIN economydata on staaten.staat_id = economydata.staat_i
group by staaten.staat_id
)
and i suggest the use of explicit join instead that where clause ... the code is more clear