[help]求一个更新 SQL
create table a_tbl(
pka int primary key,
a decimal(10,2)
)
create table b_tbl(
pkb int primary key,
fk int not null,
b decimal(10,2)
)
b_tbl.fk:a_tbl.pka=n:1
b_tbl.fk对应于a_tbl.pka
现在要把b_tbl.b更新为a_tbl.a/(对应b_tbl中记录条数),就一个sql可以完成吧?
本来想
update b_tbl
set b = a.a/ count(b_tbl.fk)
from b_tbl,a_tbl
where a_tbl.pka=b_tbl.fk
group by b_tbl.fk
结果:Server: Msg 157, Level 15, State 1, Line 2
An aggregate may not appear in the set list of an UPDATE statement.