method

join_to_update

v5.0.0.1 - Show latest stable - 0 notes - Class: ActiveRecord::ConnectionAdapters::DatabaseStatements

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What's this?

join_to_update(update, select, key) public

The default strategy for an UPDATE with joins is to use a subquery. This doesn’t work on MySQL (even when aliasing the tables), but MySQL allows using JOIN directly in an UPDATE statement, so in the MySQL adapters we redefine this to do that.

Show source

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 355
      def join_to_update(update, select, key) # :nodoc:
        subselect = subquery_for(key, select)

        update.where key.in(subselect)
      end

join_to_update

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