Rails - Using join with custom-named associations

ruby-on-rails ruby postgresql activerecord ruby-on-rails-5

where expects the actual table name, it just inserts it in SQL:

Article.where(whatever: {you: 'want'}).to_sql=> "SELECT `articles`.* FROM `articles` WHERE `whatever`.`you` = 'want'"

So you may use:

Measurement.joins(:examination).where(test_structures: { year: 2016, month: 5 })

But it's not good

Then you depend on table name while Model should abstract such things. You could use merge:

Measurement.joins(:examination).merge(TestStructure.where(year: 2016, month: 5))

ruby-on-rails ruby postgresql activerecord ruby-on-rails-5

For joins you use the association name, but for where you need to use the table name

Measurement.joins(:examination).where(test_structures: { year: 2016, month: 5 })

Measurement.joins(:examination).where('test_structures.year': 2016, 'test_structures.month': 5 )

ruby-on-rails ruby postgresql activerecord ruby-on-rails-5

In this example table name examinations should be provided instead of an association name examination in the where method.

Measurement.jons(:examination).where(examinations: { year: 2016, month: 5 })

CodeHunter