Question

Suppose I have the following two objects:

first_name_relation = User.where(:first_name => 'Tobias') # ActiveRecord::Relation
last_name_relation  = User.where(:last_name  => 'Fünke') # ActiveRecord::Relation

is it possible to combine the two relations to produce one ActiveRecord::Relation object containing both conditions?

Note: I’m aware that I can chain the wheres to get this behavior, what I’m really interested in is the case where I have two separate ActiveRecord::Relation objects.

Answer 1

If you want to combine using AND (intersection), use merge:

first_name_relation.merge(last_name_relation)

If you want to combine using OR (union), use or^†:

first_name_relation.or(last_name_relation)

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^† Only in ActiveRecord 5+; for 4.2 install the where-or backport.