Django-如何在ORM中执行此查询

Question

Hello everybody I'm trying to make this query:

SELECT * 
FROM dashboard_informe inf
INNER JOIN dashboard_servicio serv ON inf.servicio_id = serv.id
WHERE serv.nombre LIKE 'Inventario' AND inf.nombre LIKE 'Inventario%'

and I don't know how to make it, I tried this:

b = Servicio.objects.all().values_list('id')
r = Informe.objects.filter(servicio_id=b)

And it gives me an error: 'The QuerySet value for an exact lookup must be limited to ' ValueError: The QuerySet value for an exact lookup must be limited to one result using slicing.

There are someway to do that? or maybe is better create a Store Procedure with that query?

Forward thanks!

Answer 1

I think you are looking for the __in field lookup :

b = Servicio.objects.filter(nombre__startswith='Inventario').values('id')
r = Informe.objects.filter(servicio_id__in=b)

Django will convert the first query to a subquery resulting in SQL looking something like this:

SELECT ... 
FROM dashboard_informe inf 
WHERE inf.id IN (
    SELECT s.id 
    FROM dashboard_servicio s 
    WHERE s.nombre LIKE 'Inventario%'
);

Answer 2

SELECT * 
FROM dashboard_informe inf
INNER JOIN dashboard_servicio serv ON inf.servicio_id = serv.id
WHERE serv.nombre LIKE 'Inventario' AND inf.nombre LIKE 'Inventario%'

r = Informe.objects.filter(servicio__nombre='Inventario', nombre__startswith='Inventario')

Answer 3

Better to use values_list()

b = Servicio.objects.all().values_list('id', flat=True) r = Informe.objects.filter(servicio_id__in=b)