The vet wonders how old the oldest animal of each kind is. Group the pets table by kind and pick two columns: the kind, and the biggest age in that group.
The tables
owners
id
name
city
phone
1
Lena
Oslo
555-0101
2
Marco
Rome
NULL
3
Priya
Oslo
555-0103
4
Omar
Cairo
NULL
5
Sofia
Rome
555-0105
5 rows
pets
id
name
kind
age
weight
owner_id
1
Biscuit
dog
3
12
1
2
Mochi
cat
5
4
1
3
Pepper
dog
8
20
2
4
Nemo
fish
1
NULL
3
5
Luna
cat
2
3
3
6
Rex
dog
11
30
NULL
7
Kiwi
bird
4
NULL
5
8
Tofu
cat
7
5
NULL
8 rows
owners
id
name
city
phone
1
Lena
Oslo
555-0101
2
Marco
Rome
NULL
3
Priya
Oslo
555-0103
4
Omar
Cairo
NULL
5
Sofia
Rome
555-0105
5 rows
pets
id
name
kind
age
weight
owner_id
1
Biscuit
dog
3
12
1
2
Mochi
cat
5
4
1
3
Pepper
dog
8
20
2
4
Nemo
fish
1
NULL
3
5
Luna
cat
2
3
3
6
Rex
dog
11
30
NULL
7
Kiwi
bird
4
NULL
5
8
Tofu
cat
7
5
NULL
8 rows
query.sql
-- your code here: group by kind, MAX(age) finds the biggest age in each group
SELECT kind, age
FROM pets;
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Result
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