- 表基本结构
- 合并列
select t.student,decode(t.java,'','','java') 科目, t.java
from student t
union
select t.student,decode(t.c,'','','c') 科目, t.c
from student t
- 输出结果
select t.student,decode(t.java,'','','java') 科目, t.java
from student t
union
select t.student,decode(t.c,'','','c') 科目, t.c
from student t