一个关于嵌套sql语句的问题，update语句
sql = "update ASSET a set a.coin=(select b.cost from HUMANSOURCE b where b.hsId=7)
意思是 A 表 ASSET
B 表 HUMANSOURCE
把A表的coin字段设成从B表查找出来的值，sql语句怎么写啊？我那样写出错。谢谢！
[解决办法]
update ASSET set coin=(select b.cost from HUMANSOURCE b where b.hsId=7)
[解决办法]
sql = "update ASSET a set a.coin in (select b.cost from HUMANSOURCE b where b.hsId=7)
[解决办法]
你两表之间没有根据就没有建立联系，当然不能那要写了
update ASSET set coin=(select cost from HUMANSOURCE where hsId=7)
[解决办法]
ql = "update ASSET a set a.coin=(select cost from HUMANSOURCE where b.hsId=7)
