更改gb_groupd里的chargingrulesname的值
UPDATE tb_group
SET tb_group.chargingrulesname =tb_chargingrules.chargingrulesname
from tb_group inner join tb_chargingrules on tb_group.chargingrulesid=tb_chargingrules.id
语句一
UPDATE A SET A.c2 =B.c3
from A ,B
where A.c1=B.c1
语句二
UPDATE A
SET A.c2 =B.c3
from A inner join B on A.c1=B.c1