usando
exists() para obter todos os clientes e tags quando esse cliente tiver uma tag de índice 1:select ct.customernumber, ct.tagindex, c.date
from customers c
inner join customers_tags ct
on c.customernumber = ct.customernumber
where exists (
select 1
from customers_tags i
where i.customernumber = ct.customernumber
and i.tagindex = 1
)
ou usando
in() :select ct.customernumber, ct.tagindex, c.date
from customers c
inner join customers_tags ct
on c.customernumber = ct.customernumber
where c.customernumber in (
select i.customernumber
from customers_tags i
where i.tagindex = 1
)
