检查has_many关系中的所有记录是否与Rails SQL查询中的条件匹配

Question

I am attempting to create an SQL query that filters based on a specific attribute of a record in a has_many relationship.

I have program.tests which have a has_many ivr_engagements, and I want to find tests that have no ivr_engagements with ivr_engagement.call_hook_number ==2. Essentially the count of test.ivr_engagements with call_hook_number == 2 should be zero.

The object:

>> test.ivr_engagements
=> [#<IvrEngagement id: 281, user_id: 438431, testa_id: 508351, call_count: 1, call_hook_number: 1, qualified_response: true, ivr_application_id: 6741>, 
#<IvrEngagement id: 311, user_id: 438431, testa_id: 508351, call_count: 1, call_hook_number: 2, qualified_response: true, ivr_application_id: 6741>]

One of these ivr_engagements has a call_hook_number of 2. I would like to filter out any test that has an ivr_engagement matching that criteria.

This query is currently returning true (I want it to be false, since there is one record test.ivr_engagements with call_hook_number as 2):

>> program.tests.find(:all, :include => [:ivr_engagements], :conditions => "ivr_engagements.call_hook_number != 2").include? test
=> true
>> 

I've additionally tried:

>> program.tests.find(:all, :include => [:ivr_engagements], :conditions => "NOT EXISTS(SELECT 1 FROM ivr_engagements WHERE ivr_engagements.call_hook_number = 2)").include? test
=> false

Which I thought was working, but then it should have returned true when I removed the problem ivr_engagement:

>> test.ivr_engagements
=> [#<IvrEngagement id: 281, user_id: 438431, testa_id: 508351, call_count: 1, call_hook_number: 1, qualified_response: true, ivr_application_id: 6741>, 
#<IvrEngagement id: 311, user_id: 438431, testa_id: 508351, call_count: 1, call_hook_number: 2, qualified_response: true, ivr_application_id: 6741>]
>> test.ivr_engagements.last.destroy
=> #<IvrEngagement id: 311, user_id: 438431, testa_id: 508351, call_count: 1, call_hook_number: 2, qualified_response: true, ivr_application_id: 6741>
>> program.reload.tests.find(:all, :include => [:ivr_engagements], :conditions => "NOT EXISTS(SELECT 1 FROM ivr_engagements WHERE ivr_engagements.call_hook_number = 2)").include? test
=> false

Also tried:

>> program.tests.find(:all, :include => [:ivr_engagements], :conditions => "(SELECT count(*) FROM ivr_engagements WHERE ivr_engagements.call_hook_number = 2)=0")

But this also didn't work.

Hoping to find the correct query. Thanks in advance!

Answer 1

In that case you can work with a Join, like in your example, you already have the program, then we can go with this.

program.tests.joins(:ivr_engagements).where(:ivr_engagements => {call_hook_number: 2})

we find the tests that have ivr_engagements with call_hook_number with a value of 2. you can send conditions for the tests too in the same query.

as a side comment, if you later have another cases, the joins part, needs to be like the relationship, singular or plural, but the second, on the where, needs to be plural, because it's the name of the table. (in this case is the same, but if you are looking for a belongs to, it matters)

Answer 2

Get test_ids of programs

test_ids = program.tests.pluck(:id)

Now get IvrEngagement according to your condition.

IvrEngagement.where("testa_id IN (?) AND call_hook_number = ?", test_ids, 2)

Alternatively you can also try: =>

Test.includes(:ivr_engagements).where("ivr_engagements.call_hook_number = ?", 2).distinct