Method: ROM::SQL::Relation::Reading#exists

Defined in:
lib/rom/sql/relation/reading.rb

#exists(other, condition = nil) ⇒ SQL::Relation

Restrict with rows from another relation. Accepts only SQL relations and uses the EXISTS clause under the hood

Examples:

using associations

users.exists(tasks)

using provided condition

users.exists(tasks, tasks[:user_id] => users[:id])

Parameters:

  • other (SQL::Relation) —

    The other relation

  • condition (Hash, Object) (defaults to: nil) —

    An optional join condition

Returns:



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# File 'lib/rom/sql/relation/reading.rb', line 941

def exists(other, condition = nil)
  join_condition = condition || associations[other.name].join_keys
  where(other.where(join_condition).dataset.exists)
end