实例说明
资料表结构(红色为主键)==>
主表:TEST_PART_COST_TAB(料号资料表)
PART_NO VARCHAR2(20)
PART_NAME VARCHAR2(50)
从表:TEST_PART_COST_DT_TAB(料号成本资料表)
PART_NO VARCHAR2(10)
COST_ID VARCHAR2(5)
COST NUMBER
数据==>
主表资料:
PART_NO PART_NAME
1 1000 name1000
2 1001 name1001
从表资料:
PART_NO COST_ID COST
1 1000 100 1.1
2 1000 200 1.2
3 1000 300 1.3
4 1000 321 1.321
5 1001 100 2.1
交叉资料==>
SQL语句产生的结果
PART_NO PART_NAME COST_100 COST_200 COST_300 COST_321
1 1000 name1000 1.1 1.2 1.3 1.321
2 1001 name1001 2.1 0 0 0
具体的交叉SQL语句写法:
select a.part_no,a.part_name,
--sum(b.cost)
sum(case when b.cost_id = '100' then b.cost else 0 end) as cost_100,
sum(case when b.cost_id = '200' then b.cost else 0 end) as cost_200,
sum(case when b.cost_id = '300' then b.cost else 0 end) as cost_300,
sum(case when b.cost_id = '321' then b.cost else 0 end) as cost_321
from test_part_cost_tab a,test_part_cost_dt_tab b
where a.part_no = b.part_no
group by a.part_no,a.part_name
PS: 若主表有资料,从表没有资料时,交叉后会没有相应的资料
解决办法是在WHERE条件里用外连接
where a.part_no = b.part_no(+)
参考资料:
http://www.cnblogs.com/iouniuniu/archive/2004/04/05/5238.aspx ==>此文的语法与本文的语法不同
