相关疑难解决方法(0)

这是Informix更新的正确语法吗？

update table1
set table1.code = 100
from table1 a, table2 b, table3 c
where a.key = c.key
a.no = b.no
a.key = c.key
a.code = 10
b.tor = 'THE'
a.group = 4183
a.no in ('1111','1331','1345')

我得到了通用-201'发生语法错误'的消息,但我看不出有什么问题.