I have been trying to get some campaigns from a table based on some conditions from the relation table.

await prisma.campaigns.findMany({
        select:{
            url:true
        },
        where: {
            status:{
                eq: 1
            },
            AND: {
                {
                    // some conditions
                },
                {
                    // [BUG] relation based condition. 
                    OR: [
                        {
                            offer_devices: undefined
                        },
                        {
                            // condition based on offer devices.
                        }
                    ]
                },
            }
        }
    })

In this, if the offer_devices relation is null, then the condition is not working. I have tried to comment on the relation condition and it works. Looks like this condition has the issue.

{
	offer_devices: undefined
}

What is the relation of campaigns and offer_devices in your schema?

(campaigns) one to many relation (devices).

As it’s a 1-many relation, you need to use this:

await prisma.campaign.findMany({
    where: {
      status: 1,
      AND: [{ OR: [{ offer_devices: { none: {} } }] }],
    },
  })

This will find campaigns with no offer_devices.

Got it.