-- discord_user_roles
select count(distinct dur.discord_user_id)
from discord_user_roles dur
 left join discord_user du on dur.discord_user_id = du.discord_user_id
where du.discord_user_id is null;

-- discord_messages (based on author_user_id)
select count(distinct dm.author_user_id)
from discord_messages dm
 left join discord_user du on dm.author_user_id = du.discord_user_id
where du.discord_user_id is null;

-- discord_messages (based on discord_channel_id)
select count(distinct dm.channel_id)
from discord_messages dm
 left join discord_channels dc on dm.channel_id = dc.discord_channel_id
where dc.discord_channel_id is null;

-- discord_presence_update
select count(distinct dpu.discord_user_id)
from discord_presence_update dpu
 left join discord_user du on dpu.discord_user_id = du.discord_user_id
where du.discord_user_id is null;

• delete orphaned records based on findings above? if agreed:

-- discord_user_roles
delete from discord_user_roles
where discord_user_id not in (select discord_user_id from discord_user);

-- discord_messages (based on author_user_id)
delete from discord_messages
where author_user_id not in (select discord_user_id from discord_user);

-- discord_messages (based on discord_channel_id)
delete from discord_messages
where channel_id not in (select discord_channel_id from discord_channels);

-- discord_presence_update
delete from discord_presence_update
where discord_user_id not in (select discord_user_id from discord_user);