Joins parent and child tables in rails

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1. Get parent objects:
Alert.joins("LEFT JOIN alert_events on alert_events.alert_id = alerts.id 

").group('alerts.id').select('alerts.*')


2. Get Child Object:


 AlertEvent.joins("INNER JOIN alerts on alerts.id = alert_events.alert_id 
").group('alert_events.id').select('alert_events.*')

Active record for child object
AlertEvent.joins(:alert).where(alerts: {category: 'Pay'})

3. Joins multiple tables:



  @previous_seafood_items = SeafoodItem.joins("LEFT JOIN auction_items on auction_items.itemable_id = seafood_items.id and auction_items.itemable_type = 'SeafoodItem' and auction_items.auction_id is NULL")
    .group('seafood_items.id')
    .select('seafood_items.*')
    .where(user_id: current_user.id )

    .paginate(:page => params[:page], :per_page => 20)
Experienced Ruby on Rails and Web Developer having 11+ years experience in Ruby & Ruby on Rails framework, TTD, Rspec. Expert on Git, SVN , Git Hook, Bitbucket. I use MySQL, MongoDB , PostgreSQL & Sqlite for Database Management. In front-end development I use HTML5 / HAML, CSS3 / SCSS, javascript / coffeescript. I also know about the deploy the applications on VPS Server i.e AWS EC2, Heroku, Ditital Ocean, Hostgator, Site5, BlueHost, AWS Load Balancing, Elastic Beanstalk, AWS S3 e.t.c ☆ Frameworks ☆ Ruby on Rails, Sinatra ☆ Database ☆ - PostgreSQL, MySQL, SQLite, - MongoDB, Amazon DynamoDB,AWS RDS. ☆ Front end Techniques ☆ - ReactJS, Angular js, Node js, Javascript, JQuery, HTML, CSS - Twitter Bootstrap, Coffeescript. Why hire me? * Master degree in Computer Science * 6 years professional experiences and 10+ projects completed * Available all day long, 7 days/24 hours * Good communication skills with fluent English * Self-motivated, fast-learner and "I can do" mind * Quality insurance and fast delivery

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