这个比较简单，用||或concat函数可以实现
- select concat(id,username) str from app_user
- select id||username str from app_user
字符串转多列
实际上就是拆分字符串的问题，可以使用 substr、instr、regexp_substr函数方式
字符串转多行
使用union all函数等方式
wm_concat函数
- create table test(id number,name varchar2(20));
- insert into test values(1,'a');
- insert into test values(1,'b');
- insert into test values(1,'c');
- insert into test values(2,'d');
- insert into test values(2,'e');
效果1 : 行转列 ，默认逗号隔开
- select wm_concat(name) name from test;
效果2: 把结果里的逗号替换成"|"
- select replace(wm_concat(name),',','|') from test;
效果3: 按ID分组合并name
- select id,wm_concat(name) name from test group by id;
sql语句等同于下面的sql语句
- -------- 适用范围：8i,9i,10g及以后版本 （ MAX + DECODE ）
- select id, max(decode(rn, 1, name, null)) || max(decode(rn, 2, ','||name, null)) || max(decode(rn, 3, ','||name, null)) str
- from (select id, name ,row_number() over(partition by id order by name) as rn from test) t group by id order by 1;
- -------- 适用范围：8i,9i,10g及以后版本 （ ROW_NUMBER + LEAD ）
- select id, str from (select id,row_number() over(partition by id order by name) as rn,name || lead(',' || name, 1)
- over(partition by id order by name) || lead(',' || name, 2) over(partition by id order by name) || lead(',' || name, 3)
- over(partition by id order by name) as str from test) where rn = 1 order by 1;
- -------- 适用范围：10g及以后版本 （ MODEL ）
- select id, substr(str, 2) str from test model return updated rows partition by(id) dimension by(row_number()
- over(partition by id order by name) as rn) measures (cast(name as varchar2(20)) as str) rules upsert iterate(3)
- until(presentv(str[iteration_number + 2], 1, 0)=0) (str[0] = str[0] || ',' || str[iteration_number + 1]) order by 1;
- -------- 适用范围：8i,9i,10g及以后版本 （ MAX + DECODE ）
- select t.id id, max(substr(sys_connect_by_path(t.name, ','), 2)) str from (select id, name, row_number()
- over(partition by id order by name) rn from test) t start with rn = 1 connect by rn = prior rn + 1 and id = prior id
- group by t.id;
懒人扩展用法:
案例: 我要写一个视图,类似"create
or replace view as select 字段1,...字段50 from tablename"
,基表有50多个字段,要是靠手工写太麻烦了,有没有什么简便的方法? 当然有了,看我如果应用wm_concat来让这个需求变简单，假设我的APP_USER表中有（id,username,password,age）4个字段。查询结果如下
- /** 这里的表名默认区分大小写 */
- select 'create or replace view as select '|| wm_concat(column_name) || ' from APP_USER' sqlStr
- from user_tab_columns where table_name='APP_USER';
利用系统表方式查询
- select * from user_tab_columns
Oracle 11g 行列互换 pivot 和 unpivot
说明
在Oracle 11g中，Oracle
又增加了2个查询：pivot（行转列） 和unpivot（列转行）
参考：http://blog.csdn.NET/tianlesoftware/article/details/7060306、http://www.oracle.com/technetwork/cn/articles/11g-pivot-101924-zhs.html
google 一下，网上有一篇比较详细的文档：http://www.oracle-developer.net/display.php?id=506
pivot 列转行
测试数据
(id，类型名称，销售数量)，案例：根据水果的类型查询出一条数据显示出每种类型的销售数量。
- create table demo(id int,name varchar(20),nums int); ---- 创建表
- insert into demo values(1, '苹果', 1000);
- insert into demo values(2, '苹果', 2000);
- insert into demo values(3, '苹果', 4000);
- insert into demo values(4, '橘子', 5000);
- insert into demo values(5, '橘子', 3000);
- insert into demo values(6, '葡萄', 3500);
- insert into demo values(7, '芒果', 4200);
- insert into demo values(8, '芒果', 5500);
分组查询
（当然这是不符合查询一条数据的要求的）
- select name, sum(nums) nums from demo group by name
行转列查询
- select * from (select name, nums from demo) pivot (sum(nums) for name in ('苹果' 苹果, '橘子', '葡萄', '芒果'));
注意：
pivot（聚合函数 for 列名 in（类型）） ，其中 in(‘’) 中可以指定别名，in中还可以指定子查询，比如 select
distinct code from customers
当然也可以不使用pivot函数，等同于下列语句，只是代码比较长，容易理解
- ------ 多项子查询
- select * from （select sum(nums) 苹果 from demo where name='苹果'）,（select sum(nums) 橘子 from demo where name='橘子'）,
- （select sum(nums) 葡萄 from demo where name='葡萄'）,（select sum(nums) 芒果 from demo where name='芒果'）;
- ------ decode 函数利用
- select sum(decode(name,'苹果',nums)) 苹果, sum(decode(name,'橘子',nums)) 橘子,
- sum(decode(name,'葡萄',nums)) 葡萄, sum(decode(name,'芒果',nums)) 芒果 from demo
unpivot
行转列
顾名思义就是将多列转换成1列中去
案例：现在有一个水果表，记录了4个季度的销售数量，现在要将每种水果的每个季度的销售情况用多行数据展示。
创建表和数据
- create table Fruit(id int,name varchar(20), Q1 int, Q2 int, Q3 int, Q4 int);
- insert into Fruit values(1,'苹果',1000,2000,3300,5000);
- insert into Fruit values(2,'橘子',3000,3000,3200,1500);
- insert into Fruit values(3,'香蕉',2500,3500,2200,2500);
- insert into Fruit values(4,'葡萄',1500,2500,1200,3500);
- select * from Fruit
列转行查询
- select id , name, jidu, xiaoshou from Fruit unpivot (xiaoshou for jidu in (q1, q2, q3, q4) )
注意： unpivot没有聚合函数，xiaoshou、jidu字段也是临时的变量
同样不使用unpivot也可以实现同样的效果，只是sql语句会很长，而且执行速度效率也没有前者高
- select id, name ,'Q1' jidu, (select q1 from fruit where id=f.id) xiaoshou from Fruit f
- union
- select id, name ,'Q2' jidu, (select q2 from fruit where id=f.id) xiaoshou from Fruit f
- union
- select id, name ,'Q3' jidu, (select q3 from fruit where id=f.id) xiaoshou from Fruit f
- union
- select id, name ,'Q4' jidu, (select q4 from fruit where id=f.id) xiaoshou from Fruit f
。。。。
oracle 12c 关于wm_concat 的替换；LISTAGG
https://blog.csdn.net/tb_problem/article/details/80650334
oracle行转列（动态行转不定列)
/*物料 需要数量 需要仓库 现存量仓库 现存量仓库数量 批次
A1
2 C1 C1 20 123
A1
2 C1 C2 30 111
A1
2 C1 C2 20 222
A1
2 C1 C3 10 211
A2
3 C4 C1 40 321
A2
3 C4 C4 50 222
A2
3 C4 C4 60 333
A2
3 C4 C5 70 223
我需要把上面的查询结果转换为下面的。
物料 需要数量 需要仓库 C1 C2 C3 C4 C5
A1
2 C1 20 50 10 0 0
A2 3 C4 40 0 0 110
70
*/
---------------------------------------------------------------建表
----------------判断表是否存在
declare
num number;
begin
select count(1) into num from user_tables where table_name='TEST';
if num>0 then
execute
immediate 'drop table TEST';
end if;
end;
----------------建表
CREATE
TABLE TEST(
WL
VARCHAR2(10),
XYSL
INTEGER,
XYCK
VARCHAR2(10),
XCLCK
VARCHAR2(10),
XCLCKSL
INTEGER,
PC INTEGER
);
----------------第一部分测试数据
INSERT
INTO TEST VALUES('A1', 2, 'C1', 'C1' , 20, 123);
INSERT
INTO TEST VALUES('A1', 2, 'C1', 'C2' , 30, 111);
INSERT
INTO TEST VALUES('A1', 2, 'C1', 'C2' , 20, 222);
INSERT
INTO TEST VALUES('A1', 2, 'C1', 'C3' , 10, 211);
INSERT
INTO TEST VALUES('A2', 3, 'C4', 'C1' , 40, 321);
INSERT
INTO TEST VALUES('A2', 3, 'C4', 'C4' , 50, 222);
INSERT
INTO TEST VALUES('A2', 3, 'C4', 'C4' , 60, 333);
INSERT
INTO TEST VALUES('A2', 3, 'C4', 'C5' , 70, 223);
COMMIT;
--select * from test;
---------------------------------------------------------------行转列的存储过程
CREATE OR REPLACE PROCEDURE P_TEST IS
V_SQL VARCHAR2(2000);
CURSOR CURSOR_1 IS SELECT DISTINCT T.XCLCK FROM TEST T ORDER BY XCLCK;
BEGIN
V_SQL
:= 'SELECT WL,XYSL,XYCK';
FOR V_XCLCK IN
CURSOR_1
LOOP
V_SQL := V_SQL || ',' || 'SUM(DECODE(XCLCK,''' || V_XCLCK.XCLCK ||
''',XCLCKSL,0)) AS ' || V_XCLCK.XCLCK;
END LOOP;
V_SQL := V_SQL
|| ' FROM TEST GROUP BY WL,XYSL,XYCK ORDER BY WL,XYSL,XYCK';
--DBMS_OUTPUT.PUT_LINE(V_SQL);
V_SQL :=
'CREATE OR REPLACE VIEW RESULT AS '|| V_SQL;
--DBMS_OUTPUT.PUT_LINE(V_SQL);
EXECUTE
IMMEDIATE V_SQL;
END;
----------------------------------------------------------------结果
----------------执行存储过程，生成视图
BEGIN
P_TEST;
END;
----------------结果
SELECT
* FROM RESULT T;
WL XYSL
XYCK C1 C2 C3 C4 C5
----------
--------------------------------------- ---------- ---------- ----------
---------- ---------- ----------
A1 2
C1 20 50 10 0 0
A2 3
C4 40 0 0 110 70
----------------第二部分测试数据
INSERT
INTO TEST VALUES('A1', 2, 'C1', 'C6' , 20, 124);
INSERT
INTO TEST VALUES('A2', 2, 'C1', 'C7' , 30, 121);
INSERT
INTO TEST VALUES('A3', 2, 'C1', 'C8' , 20, 322);
COMMIT;
----------------报告存储过程，生成视图
BEGIN
P_TEST;
END;
----------------结果
SELECT
* FROM RESULT T;
WL XYSL
XYCK C1 C2 C3 C4 C5 C6 C7 C8
-----
----- -------- ------- -------- ---------- ---------- ---------- ----------
---------- ----------
A1 2 C1 20 50 10 0 0 20 0 0
A2 2 C1 0 0 0 0 0 0 30 0
A2 3 C4 40 0 0 110 70 0 0 0
A3 2 C1 0 0 0 0 0 0 0 20
---------------
删除实体
DROP VIEW RESULT;
DROP
PROCEDURE P_TEST;
DROP TABLE TEST;
Oracle12C—行列转换
-
基础示例
- 示例：查询每个部门中各个职位的总工资
-
分析：本程序所要查询的并不是一个部门的总工资，而是需要统计出各个职位的信息，最简单的做法是直接按照部门编号及职位进行分组统计，于是有了以下的查询语句
- 步骤1：按照部门编号及职位进行分组。此步骤进行了多表连接而后进行数据分组的方式完成的。但这种数据显示的方式不适合用户浏览，因为数据没有规律，而对于数据最好的浏览方式是像普通数据表那样，按照行的方式列出每一种职位的总工资。
select deptno,job,sum(sal) from emp group by deptno,job;
|
- 步骤2：针对不同的职位，应该使用不同的sal内容进行求和的统计，此时只能利用decode()函数完成判断。同时为了让多条记录在同一行上显示，可以针对每一个职位分别统计，对于该职位信息的部门应该使用0进行处理；
|
SELECT deptno, from emp group BY
|
- 步骤2中的decode函数是Oracle的专有函数，如果不使用此函数的话，就要通过如下的子查询方式来做了
|
SELECT temp.dno, SUM(president_job) , SUM(manager_job) , FROM ( SELECT deptno dno , (SELECT SUM(sal) FROM emp WHERE job='PRESIDENT' AND (SELECT SUM(sal) FROM emp WHERE job='MANAGER' AND (SELECT SUM(sal) FROM emp WHERE job='ANALYST' AND (SELECT SUM(sal) FROM emp WHERE job='CLERK' AND (SELECT SUM(sal) FROM emp WHERE job='SALESMAN' AND FROM emp e ) temp GROUP BY temp.dno ORDER BY temp.dno DESC
|
- 此时所完成的是一个基本的行列转换操作功能，并且显示的记录结果也更加清晰，但代码过于复杂；
-
pivot()函数
- 语法
|
select * | 列 [别名]... 统计函数(列)s 内容 1 [ [as]别名], 内容 2 [ [as]别名], ... ) ) [group by 分组字段1,分组字段2,....] [having 过滤条件(s)] |
核心组成说明如下： |
- 示例1：利用pivot()函数实现转换
|
SELECT * FROM (SELECT deptno , job , sal FROM PIVOT ( SUM(sal) FOR job IN ( 'PRESIDENT' AS president_job , 'MANAGER' AS manager_job , 'ANALYST' AS analyst_job , 'CLERK' AS clerk_job , 'SALESMAN' AS salesman_job ) ) ORDER BY deptno
|
-
拓展：使用XML与ANY
- 如果在使用pivot()函数时增加了XML显示，可以利用ANY设置所要操作的所有数据
|
SELECT * FROM (SELECT deptno , job , sal FROM PIVOT XML ( SUM(sal) FOR job IN (ANY) ) ORDER BY deptno |
- 这样就会以XML的形式显示数据，不过ANY只能用于PIVOT
XML操作里，并不能用于之前的PIVOT()函数中
|
|
- 示例2：使用PIVOT()函数只能够完成一种信息的统计，在了解了不同职位的总工资之外，还希望知道部门的人数及最高和最低工资，就需要利用OVER
PARTITION BY语句完成
|
SELECT * FROM ( SELECT job ,deptno , sal, SUM(sal) OVER(PARTITION BY deptno) sum_sal MAX(sal) OVER(PARTITION BY deptno) max_sal MIN(sal) OVER(PARTITION BY deptno) FROM emp) PIVOT ( SUM(sal) FOR job IN ( 'PRESIDENT' AS president_job , 'MANAGER' AS manager_job , 'ANALYST' AS analyst_job , 'CLERK' AS clerk_job , 'SALESMAN' AS salesman_job ) ) ORDER BY deptno
|
- 示例3：设置多个统计函数，查询每个部门不同职位的总工资，以及每个部门不同职位ide最高工资
|
SELECT * FROM (SELECT deptno , job , sal FROM PIVOT ( SUM(sal) AS sum_sal , MAX(sal) AS FOR job IN ( 'PRESIDENT' AS president_job , 'MANAGER' AS manager_job , 'ANALYST' AS analyst_job , 'CLERK' AS clerk_job , 'SALESMAN' AS salesman_job ) ) ORDER BY deptno
|
-
unpivot()函数
- 首先，使用下面的sql语句更新基础代码：
|
ALTER TABLE emp ADD (sex VARCHAR2(10) DEFAULT UPDATE emp SET sex='女' WHERE TO_CHAR(hiredate,'yyyy')='1981' COMMIT |
- 示例1：设置多个统计列。上面的代码更新后，会在emp表中增加一个性别列，现在要求使用PIVOT()函数针对不同职位的不同性别进行总工资的统计，可以在for语句中设置多个列
|
SELECT * FROM (SELECT deptno , job , sal , sex FROM PIVOT ( SUM(sal) AS sum_sal , MAX(sal) AS FOR (job, sex) IN ( ('MANAGER','男') AS manager_male_JOB , ('MANAGER','女') AS manager_female_JOB , ('CLERK','男') AS clerk_male_JOB , ('CLERK','女') AS clerk_female_JOB ) ) ORDER BY deptno
|
- 通过PIVOT()函数可以将行转换为列，反过来，也可以使用UNPIVOT()函数将列重新转换为行
- UNPIVOT()函数语法：
|
select * | 列 [别名]... 统计函数（列）s 内容1 内容2 .... 内容n ) ) [where 条件(s)] [group by 分组字段1,分组字段2,....] [having 过滤条件(s)] [order by 排序字段 asc|desc]; |
此函数与pivot()定义类似，不同的地方在于两个选项； |
- 示例2：
|
WITH temp AS ( SELECT * FROM (SELECT deptno , job , sal FROM PIVOT ( SUM(sal) FOR job IN ( 'PRESIDENT' AS PRESIDENT_JOB , 'MANAGER' AS MANAGER_JOB , 'ANALYST' AS ANALYST_JOB , 'CLERK' AS CLERK_JOB , 'SALESMAN' AS SALESMAN_JOB ) ) ORDER BY deptno ) SELECT * FROM temp UNPIVOT ( sal_sum FOR job IN ( president_job AS 'PRESIDENT' , manager_job AS 'MANAGER' , analyst_job AS 'ANALYST' , clerk_job AS 'CLERK' , salesman_job AS 'SALESMAN' ) ) ORDER BY deptno ;
|
- 示例3：示例2的查询不包含Null值，可以使用INCLUDE
NULLS选项包含null值
|
WITH temp AS ( SELECT * FROM (SELECT deptno , job , sal FROM PIVOT ( SUM(sal) FOR job IN ( 'PRESIDENT' AS PRESIDENT_JOB , 'MANAGER' AS MANAGER_JOB , 'ANALYST' AS ANALYST_JOB , 'CLERK' AS CLERK_JOB , 'SALESMAN' AS SALESMAN_JOB ) ) ORDER BY deptno ) SELECT * FROM temp UNPIVOT INCLUDE NULLS( sal_sum FOR job IN ( president_job AS 'PRESIDENT' , manager_job AS 'MANAGER' , analyst_job AS 'ANALYST' , clerk_job AS 'CLERK' , salesman_job AS 'SALESMAN' ) ) ORDER BY deptno ;
|
