Oracle行轉列和列轉行
1.1、初始測試數據
表結構:TEST_TB_GRADE
Sql代碼:
1 create table TEST_TB_GRADE
2 (
3 ID NUMBER(10) not null,
4 USER_NAME VARCHAR2(20 CHAR),
5 COURSE VARCHAR2(20 CHAR),
6 SCORE FLOAT
7 )
初始數據如下圖:
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函數、聚集函數(sum),結合group by分組實現的,具體的sql如下:
Sql代碼:
1 select t.user_name,
2 sum(decode(t.course, '語文', score,null)) as CHINESE,
3 sum(decode(t.course, '數學', score,null)) as MATH,
4 sum(decode(t.course, '英語', score,null)) as ENGLISH
5 from test_tb_grade t
6 group by t.user_name
7 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代碼:
01 select t2.SCORE_GP,
02 sum(decode(t2.course, '語文', COUNTNUM,null)) as CHINESE,
03 sum(decode(t2.course, '數學', COUNTNUM,null)) as MATH,
04 sum(decode(t2.course, '英語', COUNTNUM,null)) as ENGLISH
05 from (
06 select t.course,
07 case when t.score <60 then '00-60'
08 when t.score >=60 and t.score <80 then '60-80'
09 when t.score >=80 then '80-100' end as SCORE_GP,
10 count(t.score) as COUNTNUM
11 FROM test_tb_grade t
12 group by t.course,
13 case when t.score <60 then '00-60'
14 when t.score >=60 and t.score <80 then '60-80'
15 when t.score >=80 then '80-100' end
16 order by t.course ) t2
17 group by t2.SCORE_GP
18 order by t2.SCORE_GP
二、列轉行
1.1、初始測試數據
表結構: TEST_TB_GRADE2
Sql代碼:
1 create table TEST_TB_GRADE2
2 (
3 ID NUMBER(10) not null,
4 USER_NAME VARCHAR2(20 CHAR),
5 CN_SCORE FLOAT,
6 MATH_SCORE FLOAT,
7 EN_SCORE FLOAT
8 )
初始數據如下圖:
Sql代碼:
1 select user_name, 'CN_SCORE' COURSE , CN_SCORE as SCORE from test_tb_grade2
2 union
3 select user_name, 'MATH_SCORE' COURSE, MATH_SCORE as SCORE from test_tb_grade2
4 union
5 select user_name, 'EN_SCORE' COURSE, EN_SCORE as SCORE from test_tb_grade2
6 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代碼:
1 create table TEST_TB_GRADE3
2 (
3 USER_NAME VARCHAR2(20 CHAR),
4 COURSE VARCHAR2(20 CHAR),
5 SCORE FLOAT
6 )
再執行下面的sql:
Sql代碼:
1 insert all
2 into test_tb_grade3(USER_NAME,COURSE,SCORE) values(user_name, '語文', CN_SCORE)
3 into test_tb_grade3(USER_NAME,COURSE,SCORE) values(user_name, '數學', MATH_SCORE)
4 into test_tb_grade3(USER_NAME,COURSE,SCORE) values(user_name, '英語', EN_SCORE)
5 select user_name, CN_SCORE, MATH_SCORE, EN_SCORE from test_tb_grade2;
6 commit;
別忘記commit操作,然後再查詢TEST_TB_GRADE3,發現表中的數據就是列轉成行了。
表結構:TEST_TB_GRADE
Sql代碼:
1 create table TEST_TB_GRADE
2 (
3 ID NUMBER(10) not null,
4 USER_NAME VARCHAR2(20 CHAR),
5 COURSE VARCHAR2(20 CHAR),
6 SCORE FLOAT
7 )
初始數據如下圖:
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函數、聚集函數(sum),結合group by分組實現的,具體的sql如下:
Sql代碼:
1 select t.user_name,
2 sum(decode(t.course, '語文', score,null)) as CHINESE,
3 sum(decode(t.course, '數學', score,null)) as MATH,
4 sum(decode(t.course, '英語', score,null)) as ENGLISH
5 from test_tb_grade t
6 group by t.user_name
7 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代碼:
01 select t2.SCORE_GP,
02 sum(decode(t2.course, '語文', COUNTNUM,null)) as CHINESE,
03 sum(decode(t2.course, '數學', COUNTNUM,null)) as MATH,
04 sum(decode(t2.course, '英語', COUNTNUM,null)) as ENGLISH
05 from (
06 select t.course,
07 case when t.score <60 then '00-60'
08 when t.score >=60 and t.score <80 then '60-80'
09 when t.score >=80 then '80-100' end as SCORE_GP,
10 count(t.score) as COUNTNUM
11 FROM test_tb_grade t
12 group by t.course,
13 case when t.score <60 then '00-60'
14 when t.score >=60 and t.score <80 then '60-80'
15 when t.score >=80 then '80-100' end
16 order by t.course ) t2
17 group by t2.SCORE_GP
18 order by t2.SCORE_GP
二、列轉行
1.1、初始測試數據
表結構: TEST_TB_GRADE2
Sql代碼:
1 create table TEST_TB_GRADE2
2 (
3 ID NUMBER(10) not null,
4 USER_NAME VARCHAR2(20 CHAR),
5 CN_SCORE FLOAT,
6 MATH_SCORE FLOAT,
7 EN_SCORE FLOAT
8 )
初始數據如下圖:
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裏面的union,具體的sql語句如下:
Sql代碼:
1 select user_name, 'CN_SCORE' COURSE , CN_SCORE as SCORE from test_tb_grade2
2 union
3 select user_name, 'MATH_SCORE' COURSE, MATH_SCORE as SCORE from test_tb_grade2
4 union
5 select user_name, 'EN_SCORE' COURSE, EN_SCORE as SCORE from test_tb_grade2
6 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代碼:
1 create table TEST_TB_GRADE3
2 (
3 USER_NAME VARCHAR2(20 CHAR),
4 COURSE VARCHAR2(20 CHAR),
5 SCORE FLOAT
6 )
再執行下面的sql:
Sql代碼:
1 insert all
2 into test_tb_grade3(USER_NAME,COURSE,SCORE) values(user_name, '語文', CN_SCORE)
3 into test_tb_grade3(USER_NAME,COURSE,SCORE) values(user_name, '數學', MATH_SCORE)
4 into test_tb_grade3(USER_NAME,COURSE,SCORE) values(user_name, '英語', EN_SCORE)
5 select user_name, CN_SCORE, MATH_SCORE, EN_SCORE from test_tb_grade2;
6 commit;
別忘記commit操作,然後再查詢TEST_TB_GRADE3,發現表中的數據就是列轉成行了。