如 表1

itemno   saleqty    saleprice

123        80        5.5         

321        70        5.6

124        60        5.7

表2

itemno1       price     type

123             3        0

123             4        1

321             2        1

124             4        2

查出语句变成这样

itemno         saleqty   saleprice  price1   price2    price3

 123            80         5.5        3        4          0
  
 321            70         5.6        0        2          0

 124            60         5.7        0        0          4
 
price1,price2,price3,根据type来决定的

price1=0,price2=1,price3=2

两种方法：
方法一：
表1和表2内联结，price1~price3字段用caseb函数进行判断即可。
方法二：
表1三次和表2内联结，表2在三次联结中所用的条件分别是：
    type=0；type=1；type=2

        方法如下:
 drop table m1
drop table m2
create table m1(itemno int,saleqty int,saleprice float(10) )
insert into m1(itemno,saleqty,saleprice)values(123,80,5.5)
insert into m1(itemno,saleqty,saleprice)values(321,70,5.6)
insert into m1(itemno,saleqty,saleprice)values(124,60,5.7)
select * from m1
create table m2(itemno int,price int,type int)
insert into m2(itemno,price,type)values(123,3,0)
insert into m2(itemno,price,type)values(123,4,1)
insert into m2(itemno,price,type)values(321,2,1)
insert into m2(itemno,price,type)values(124,4,2)
select * from m2

select m1.itemno,saleqty,saleprice, sum(case type when 0 then price else 0 end ) price1,
                      sum(case type when 1 then price else 0 end)price2,
                      sum(case type when 2 then price else 0 end )price3
           from m1 inner join m2 on  m1.itemno=m2.itemno group by m1.itemno,m1.saleqty,saleprice order by m1.saleqty desc