从头开始学Oracle--------行转列

 

with temp as(
select '大宇' name ,'语文' subject,'85' score from dual union all
select '大宇' name ,'数学' subject,'81' score from dual union all
select '小宇' name ,'语文' subject,'77' score from dual union all
select '小宇' name ,'数学' subject,'72' score from dual union all
select '小大宇' name ,'语文' subject,'58' score from dual 
)
select name,
-- 如果subject是语文的话，这一列取score，如果score为空则取0
max(decode(subject, '语文', score, '0')) as SCORE_语文,
max(decode(subject, '数学', score, '0')) as SCORE_数学
from temp group by name;

with temp as(
select '四川省' nation ,'成都市' city,'第一' ranking from dual union all
select '四川省' nation ,'绵阳市' city,'第二' ranking from dual union all
select '四川省' nation ,'德阳市' city,'第三' ranking from dual union all
select '四川省' nation ,'宜宾市' city,'第四' ranking from dual union all
select '湖北省' nation ,'武汉市' city,'第一' ranking from dual union all
select '湖北省' nation ,'宜昌市' city,'第二' ranking from dual union all
select '湖北省' nation ,'襄阳市' city,'第三' ranking from dual
)
select nation,
max(decode(ranking, '第一', city, '')) as 第一,
max(decode(ranking, '第二', city, '')) as 第二,
max(decode(ranking, '第三', city, '')) as 第三,
max(decode(ranking, '第四', city, '')) as 第四
from temp group by nation;