Howdy!
> At any rate, say I have 3 tables:
>
> table plant
> id:integer
> name string
>
>
> table seed_supplier
> id: integer
> company_name: string
>
> table plant_seed_supplier
> plant_id
> seed_supplier_id
>
> plant_seed_supplier is a join table that supports a many to many
> relationship between the plant table and the seed supplier table since
> any plant may have multiple seed suppliers and any seed supplier can
> sell seeds for many different plants.
>
> I would like to be able to write a single query that basically does
> this:
>
> It will show only one distinct row for each plant in the database. It
> will show either just one seed_supplier company name associated with
> that plant, or if there is no supplier associated with that plant it
> will show the plant in a row with that field empty.
>
You do not specify what is the seed_supplier company name that should appear
in the case there is more than one
Give this (untested) query a try
SELECT name,MIN(company_name)
FROM plant a
JOIN plant_seed_supplier associative
ON plant_id = a.id
JOIN seed_supplier b
ON b.id = supplier_id
GROUP BY name
Best,
Oliveiros
