def update_counters(id, counters)
updates = counters.inject([]) { |list, (counter_name, increment)|
sign = increment < 0 ? "-" : "+"
list << "#{connection.quote_column_name(counter_name)} = COALESCE(#{connection.quote_column_name(counter_name)}, 0) #{sign} #{increment.abs}"
}.join(", ")
if id.is_a?(Array)
ids_list = id.map {|i| quote_value(i)}.join(', ')
condition = "IN (#{ids_list})"
else
condition = "= #{quote_value(id)}"
end
update_all(updates, "#{connection.quote_column_name(primary_key)} #{condition}")
end