How to query a table with 2 foreign keys? - sql

Question

I have three tables in my android app.
Table Animal Table Group TableGroup_Animal
idAnimal idGroup idAnimal
AnimalName groupName idGroup
I want to know how to do query in order to get all the animals inside a group. The query I made is this
select
Groups.groupName
from
Groups,
Animal,
tableGrupo_Animal
where
Animal.idanimal = tableGroup_Animal.fkanimal
and
Groups.idgrupo = tableGrupo_Animal.fkgrupo
group by
group.groupName
And also this(That only shows the first row)
select
*
from
Animal
INNER JOIN " + tableGroup + " ON Animal.idanimal = Group.idGroup
where
Group.groupName = ' " + groupName +
As I said I want to get all the animals inside a group, how can I do that? Thanks

Answer 1

I recreated your database in sqlite and tested this out. This SQL works fine. I'd suggest that you rename your table "Group" as it's a reserved word in SQL and you'll have to back tick it every time as I do in this sql.
select a.AnimalName, g.groupName
from Animal a
JOIN TableGroup_Animal tga ON a.idAnimal = tga.idAnimal
JOIN `Group` g on g.idGroup= tga.idGroup;
Here's the schema I created and data to help anyone trying to prototype this.
CREATE TABLE `Animal` (
`idAnimal` INTEGER PRIMARY KEY AUTOINCREMENT UNIQUE,
`animalName` varchar(128)
);
CREATE TABLE `Group` (
`idGroup` INTEGER PRIMARY KEY AUTOINCREMENT UNIQUE,
`groupName` varchar(128)
);
CREATE TABLE `TableGroup_Animal` (
`id` INTEGER PRIMARY KEY AUTOINCREMENT UNIQUE,
`idAnimal` integer,
`idGroup` integer
);
--Seeding animal
insert into `Animal` (animalName) values ('cat');
insert into `Animal` (animalName) values ('Rat');
insert into `Animal` (animalName) values ('Zebra');
insert into `Animal` (animalName) values ('Platypus');
--seeding group
insert into `Group` (groupName) values ('small');
insert into `Group` (groupName) values ('medium');
insert into `Group` (groupName) values ('large');
---seeding group animal pivot table
insert into TableGroup_Animal (idAnimal, idGroup) values (3,2);
insert into TableGroup_Animal (idAnimal, idGroup) values (3,3);
insert into TableGroup_Animal (idAnimal, idGroup) values (1,2);
insert into TableGroup_Animal (idAnimal, idGroup) values (4,2);
insert into TableGroup_Animal (idAnimal, idGroup) values (2,1);
);
insert into TableGroup_Animal (idAnimal, idGroup) values (2,1);

Answer 2

Do this query:
select * from Animal INNER JOIN tableGrupo_Animal ON Animal.idanimal = tableGrupo_Animal.fkanimal INNER JOIN Grupos ON Grupos.idgrupo = tableGrupo_Animal.fkgrupo where Grupos.nomegrupo='wwrt'