How to Do a Union of Multiple Queryset from a Clickhouse Orm
In a Django Search App, I Want to Query a Clickhouse Database (Using the Infi. Clickhouse_Orm Library) for Pairs of Values Such as (A=1 and B>=1.5) or (A=2 and...
In a Django search app, I want to query a clickhouse database (using the infi.clickhouse_orm library) for pairs of values such as (a=1 AND b>=1.5) OR (a=2 AND b>=1). In SQL this could be done with
select * from table where a == 1 and b >= 1.5 UNION ALL select * from table where a == 2 and b >= 1
Looking at other exemples I have tried:
With the queryset defined as
qs = TABLE.objects_in(db)
qs_1 = qs.filter(A__eq=1, B__gte=1.5)
qs_2 = qs.filter(A__eq=2, B__gte=1)
The | operator
qs_union = qs_1 | qs_2
which returns
unsupported operand type(s) for |: 'QuerySet' and 'QuerySet'
The UNION operator
qs_union = qs_1.union(qs_2)
which returns
'QuerySet' object has no attribute 'union'
and the Q objects
qs_union = qs.filter(Q(A__eq=1, B__gte=1.5) | Q(A__eq=2, B__gte=1))
which returns
'Q' object has no attribute 'to_sql'
From a clickhouse models, how do you perfom a union of 2, or more, queryset?
Thanks!
1 Answer
Short answer: you should use the Q class of infi.clickhouse_orm.query, like:
from infi.clickhouse_orm.query import QThe Q-class in info.clickhouse_orm [GitHub] has a to_sql method:
class Q(object): # ... def to_sql(self, model_cls): if self._fovs: sql = ' {} '.format(self._mode).join(fov.to_sql(model_cls) for fov in self._fovs) else: if self._l_child and self._r_child: sql = '({} {} {})'.format( self._l_child.to_sql(model_cls), self._mode, self._r_child.to_sql(model_cls)) else: return '1' if self._negate: sql = 'NOT (%s)' % sql return sql
Since the errors says it can not find the to_sql, it looks like you did not use that Q-class, but Django's Q class.
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