1.多列轉成一列(列轉行)

--6列轉成兩列(列轉行)

這就是最常見的列轉行，主要原理是利用SQL裡面的union

with temp as
 (select
   a.iid_sn,
   a.product_name,
   a.sales_figures,
   a.selling_cost,
   a.pretax_profit,
   a.closing_inventory
    from is_import_detail a, is_import b
   where a.isi_sn = b.isi_sn
   and b.import_year=?
   and b.import_month=?
   and a.product_name=?)

--sql中要想實現特定的排序，可以適當加一些整數
select 1,'銷售額' as salename, sales_figures as sale
  from temp
union
select 2,'銷售成本' as salename, selling_cost as sale
  from temp
union
select 3,'稅前利潤' as salename, pretax_profit as sale
  from temp
union
select 5, '期末庫存量' as serialname, closing_inventory as serial
  from temp

2.行轉列

主要原理是利用decode函式、聚集函式(sum)，結合group by分組實現的，具體的sql如下：

select t.user_name,
       sum(decode(t.course, '語文', score, null)) as chinese,
       sum(decode(t.course, '數學', score, null)) as math,
       sum(decode(t.course, '英語', score, null)) as english
  from test_tb_grade t
 group by t.user_name
 order by t.user_name