目錄結構如下：
行轉列
列轉行
[一]、行轉列

1.1、初始測試資料

表結構：TEST_TB_GRADE

Sql程式碼
create table TEST_TB_GRADE
(
ID NUMBER(10) not null,
USER_NAME VARCHAR2(20 CHAR),
COURSE VARCHAR2(20 CHAR),
SCORE FLOAT
)
初始資料如下圖：

1.2、 如果需要實現如下的查詢效果圖：

這就是最常見的行轉列，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：
Sql程式碼
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


1.3、延伸

如果要實現對各門功課的不同分數段進行統計，效果圖如下：

具體的實現sql如下：
Sql程式碼
select t2.SCORE_GP,
sum(decode(t2.course, '語文', COUNTNUM,null)) as CHINESE,
sum(decode(t2.course, '數學', COUNTNUM,null)) as MATH,
sum(decode(t2.course, '英語', COUNTNUM,null)) as ENGLISH
from (
select t.course,
case when t.score <60 then '00-60'
when t.score >=60 and t.score <80 then '60-80'
when t.score >=80 then '80-100' end as SCORE_GP,
count(t.score) as COUNTNUM
FROM test_tb_grade t
group by t.course,
case when t.score <60 then '00-60'
when t.score >=60 and t.score <80 then '60-80'
when t.score >=80 then '80-100' end
order by t.course ) t2
group by t2.SCORE_GP
order by t2.SCORE_GP

[二]、列轉行

1.1、初始測試資料
表結構：TEST_TB_GRADE2
Sql程式碼
create table TEST_TB_GRADE2
(
ID NUMBER(10) not null,
USER_NAME VARCHAR2(20 CHAR),
CN_SCORE FLOAT,
MATH_SCORE FLOAT,
EN_SCORE FLOAT
)

初始資料如下圖：

1.2、 如果需要實現如下的查詢效果圖：

這就是最常見的列轉行，主要原理是利用SQL裡面的union，具體的sql語句如下：
Sql程式碼
select user_name, '語文' COURSE , CN_SCORE as SCORE from test_tb_grade2
union select user_name, '數學' COURSE, MATH_SCORE as SCORE from test_tb_grade2
union select user_name, '英語' COURSE, EN_SCORE as SCORE from test_tb_grade2
order by user_name,COURSE

也可以利用【 insert all into ... select 】來實現，首先需要先建一個表TEST_TB_GRADE3：
Sql程式碼
create table TEST_TB_GRADE3
(
USER_NAME VARCHAR2(20 CHAR),
COURSE VARCHAR2(20 CHAR),
SCORE FLOAT
)
再執行下面的sql：

Sql程式碼
insert all
into test_tb_grade3(USER_NAME,COURSE,SCORE) values(user_name, '語文', CN_SCORE)
into test_tb_grade3(USER_NAME,COURSE,SCORE) values(user_name, '數學', MATH_SCORE)
into test_tb_grade3(USER_NAME,COURSE,SCORE) values(user_name, '英語', EN_SCORE)
select user_name, CN_SCORE, MATH_SCORE, EN_SCORE from test_tb_grade2;
commit;
別忘記commit操作，然後再查詢TEST_TB_GRADE3，發現表中的資料就是列轉成行了。