Supabase Query Builder Only Returning One Row Instead of Two

I'm using Supabase's query builder to fetch data with a foreign key relationship, but the query is only returning one row, even though I expect it to return two.

Here's the code I'm using:

const { data, error } = await supabase
.from('m_service_upsells')
.select(`*, upsell_service:m_services!m_service_upsells_upsell_service_id_fkey(*)`)
.eq('main_service_id', main_service_id);

Question: Why is the Supabase query builder returning only one row when two rows exist in the database? Is there a limitation or something I’m missing in the query builder's syntax for handling relationships?

Table Schema (simplified):

m_service_upsells: { id, main_service_id, upsell_service_id }
m_services: { id, name, description }
Relationship: m_service_upsells.upsell_service_id -> m_services.id

Any insights or suggestions would be greatly appreciated!

What I’ve Checked:

1. Database Data: I’ve confirmed that the database contains two rows with the same main_service_id.
2. Foreign Key: The foreign key relationship is correctly defined and works fine in raw SQL.
3. SQL Query: I ran the equivalent raw SQL query, and it works perfectly:

SELECT 
    m_service_upsells.*,
    json_agg(m_services.*) AS upsell_service
FROM 
    m_service_upsells
LEFT JOIN 
    m_services 
ON 
    m_service_upsells.upsell_service_id = m_services.id
WHERE 
    m_service_upsells.main_service_id = 'your_main_service_id'
GROUP BY 
    m_service_upsells.id;

Observations:

1. No errors are returned from the query builder.
2. The select() query seems to fetch only the first matching row