ORALCE 行列互换实例说明
初始表tt:
SQL> select * from tt;
STU OBJECT GRADE
---------- ---------- ----------
11 shuxue 90
12 shuxue 80
13 shuxue 80
14 shuxue 91
15 shuxue 71
11 yuwen 71
12 yuwen 81
13 yuwen 81
14 yuwen 88
15 yuwen 98
10 rows selected.
1.行-->列
SQL> select stu,sum(decode(object,'shuxue',grade)) shuxue,
sum(decode(object,'yuwen',grade)) yumen from tt
group by stu order by stu ;
STU SHUXUE YUMEN
---------- ---------- ----------
11 90 71
12 80 81
13 80 81
14 91 88
15 71 98
注：现在我们将结果保存为表dd,然后在将dd还原成tt的样子，就是列-->行。
2.列-->行
SQL> select stu,'shuxue' object,shuxue grade from dd
2 union all
3 select stu,'yuwen' object,yuwen grade from dd ;
STU OBJECT GRADE
---------- ------ ----------
11 shuxue 90
12 shuxue 80
13 shuxue 80
14 shuxue 91
15 shuxue 71
11 yuwen 71
12 yuwen 81
13 yuwen 81
14 yuwen 88
15 yuwen 98
注释：这就是ORACLE中的行列转换。
