MYSQL 一问

请问有什么错误及如何写法
SQL 语法:
UPDATE a_stock SET qb_sunrise_bal = sum( in_stock ) WHERE warehouse = 'QuarryBay' AND product = 'Sunrise' AND arrival_date BETWEEN '2014-01-01' AND '2014-04-30'

MySQL 传回：
#1111 - Invalid use of group function

You can try this to see whether it works.

UPDATE a_stock SET qb_sunrise_bal = (select sum( in_stock ) WHERE warehouse = 'QuarryBay' AND product = 'Sunrise' AND arrival_date BETWEEN '2014-01-01' AND '2014-04-30' )