title: ActiveRecord::StatementInvalid (PG::SyntaxError: ERROR: syntax error at or near "EQ"
body: <p>I want to join 3 tables to get data but with following query I've got an error: <code>ActiveRecord::StatementInvalid (PG::SyntaxError: ERROR:  syntax error at or near "EQ"</code></p>
  
  <p>query</p>
  
  <pre><code>Process.joins(process_template: :process_groups).where("process_groups IS EQ COMPANY_DATA")
  </code></pre>
  
  <p>Models explanations</p>
  
  <pre><code>model Process
  belongs_to :process_template
  
  model ProcessTemplate
  has_many :process_groups
  
  model ProcessGroup
  belongs_to :process_template
  </code></pre>