Question

SQL,两个表，用符合条件中的最小值赋值

表table1和table2。
table1字段a,b
table2字段c,d
当a=c时，用d中符合这个条件中的最小值赋值给b。
请问语句怎么写？
谢谢！
table1中a字段不唯一

Answer 1

update table1 set table1.b=(select top 1 table2.d from table2 where table1.a=table2.c order by table2.d Asc)

Answer 2

update table1 set b=(select min(d) from table2 where table1.a=table2.c)

Answer 3

update t1 set b = t3.d from t1 inner join (select c,min(d) as d from t2 group by c) as t3 on t1.a=t3.c

Answer 4

update table1 set b=(select min(d) from table2,table1 while a=c )

Answer 5

select min(left_day),atrate from Act_Table
where Act=1 group by atrate