class CanCan::ModelAdapters::Strategies::JoinedAliasExistsSubquery

def execute!
  model_class
    .joins(
      "JOIN #{quoted_table_name} AS #{quoted_aliased_table_name} ON " \
      "#{quoted_aliased_table_name}.#{quoted_primary_key} = #{quoted_table_name}.#{quoted_primary_key}"
    )
    .where("EXISTS (#{joined_alias_exists_subquery_inner_query.to_sql})")
end

def joined_alias_exists_subquery_inner_query
  model_class
    .unscoped
    .select('1')
    .left_joins(joins)
    .where(*where_conditions)
    .where(
      "#{quoted_table_name}.#{quoted_primary_key} = " \
      "#{quoted_aliased_table_name}.#{quoted_primary_key}"
    )
    .limit(1)
end