数据库 
首页 > 数据库 > 浏览文章

PostgreSQL 实现列转行问题

(编辑：jimmy 日期: 2024/11/15 浏览：3 次 )

1 测试表数据

SELECT
  relative_label_content
FROM
  frk_s.label_cor_gene
relative_label_content
------
AA
BB
CC

2 列转行写法

写法1：

string_agg

SELECT
  frwybs,
  string_agg (relative_label_content, ',') as relative_label_content
FROM
  frk_s.label_cor_gene
GROUP BY
  frwybs
relative_label_content
------------
AA,BB,CC

写法2：

array_to_string(ARRAY_AGG (text),',')

SELECT
  frwybs,
  array_to_string(
    ARRAY_AGG (DISTINCT relative_label_content),
    ','
  ) as labels_content
FROM
  frk_s.label_cor_gene
GROUP BY
  frwybs
labels_content
------------
AA,BB,CC

补充：PostgreSQL行列转换(兼容oracle pivot unpivot)

oracle11g开始内置了数据透视表pivot table这一功能，可以用来实现行列转换的功能，但是在数据量较大的时候使用性能就会较差。

pivot语法为：

SELECT ...  
FROM  ...  
PIVOT [XML]  
  (pivot_clause  
  pivot_for_clause  
  pivot_in_clause )  
WHERE ...

oracle pivot使用例子：

–创建测试表并插入数据

create table usr
(name varchar2(20),
 score int,
 class varchar2(20)
);
insert into usr values('a',20,'math');
insert into usr values('a',22,'phy');
insert into usr values('b',23,'phy');
insert into usr values('b',21,'math');
insert into usr values('c',22,'phy');
insert into usr values('c',24,'math');
insert into usr values('d',25,'math');
insert into usr values('d',23,'phy');

–使用pivot进行行列转换

SQL> select * from usr
 2 pivot(
sum(score)
for class in ('math','phy')
 3  4  5 );
NAME           'math'   'phy'
-------------------- ---------- ----------
d              25     23
a              20     22
b              21     23
c              24     22

我们还可以使用unpivot来实现列转行。

unpivot语法为：

SELECT ...  
FROM ...  
UNPIVOT [INCLUDE|EXCLUDE NULLS]  
  (unpivot_clause  
  unpivot_for_clause  
  unpivot_in_clause )  
WHERE ...

oracle unpivot使用例子：

–创建测试表并插入数据

CREATE TABLE t1 
(
  VendorID int, 
  Emp1 int, 
  Emp2 int, 
  Emp3 int, 
  Emp4 int,
  Emp5 int
); 
INSERT INTO t1 VALUES (1,4,3,5,4,4); 
INSERT INTO t1 VALUES (2,4,1,5,5,5); 
INSERT INTO t1 VALUES (3,4,3,5,4,4); 
INSERT INTO t1 VALUES (4,4,2,5,5,4); 
INSERT INTO t1 VALUES (5,5,1,5,5,5);

–使用unpivot进行列转行

SQL> select * from t1
 2 UNPIVOT(
orders for Employee in(emp1,emp2,emp3,emp4,emp5)
); 3  4 
 VENDORID EMPL   ORDERS
---------- ---- ----------
     1 EMP1     4
     1 EMP2     3
     1 EMP3     5
     1 EMP4     4
     1 EMP5     4
     2 EMP1     4
     2 EMP2     1
     2 EMP3     5
     2 EMP4     5
     2 EMP5     5
     3 EMP1     4
 VENDORID EMPL   ORDERS
---------- ---- ----------
     3 EMP2     3
     3 EMP3     5
     3 EMP4     4
     3 EMP5     4
     4 EMP1     4
     4 EMP2     2
     4 EMP3     5
     4 EMP4     5
     4 EMP5     4
     5 EMP1     5
     5 EMP2     1
 VENDORID EMPL   ORDERS
---------- ---- ----------
     5 EMP3     5
     5 EMP4     5
     5 EMP5     5
25 rows selected.

那么在pg中该如何实现oracle的pivot/unpivot的行列转行功能呢？pg中自带的tablefunc插件可以实现，我们可以使用该插件中的crosstab函数接口进行行列转换。

pg行转列例子：

–建表插入测试数据

create table tbl (seller text,se_year int,se_month int,se_amount int); 
insert into tbl values ('test1',2020,01,123456);   
insert into tbl values ('test1',2020,02,234567);   
insert into tbl values ('test1',2020,03,345678);   
insert into tbl values ('test1',2020,04,345678);   
insert into tbl values ('test1',2020,05,567890);   
insert into tbl values ('test2',2020,01,12);   
insert into tbl values ('test2',2020,02,23);   
insert into tbl values ('test2',2020,03,34);   
insert into tbl values ('test2',2020,04,45);   
insert into tbl values ('test2',2020,05,56);   
insert into tbl values ('test3',2020,03,12);   
insert into tbl values ('test3',2020,04,45);   
insert into tbl values ('test3',2020,05,56);   
insert into tbl values ('test4',2020,02,20);   
insert into tbl values ('test4',2020,03,30);   
insert into tbl values ('test4',2020,04,40);   
insert into tbl values ('test4',2020,05,50);   
insert into tbl values ('test1',2019,01,123456);   
insert into tbl values ('test1',2019,02,234567);   
insert into tbl values ('test1',2019,03,345678);   
insert into tbl values ('test1',2019,04,345678);   
insert into tbl values ('test1',2019,05,567890);   
insert into tbl values ('test1',2019,06,123456);   
insert into tbl values ('test1',2019,07,234567);   
insert into tbl values ('test1',2019,08,345678);   
insert into tbl values ('test1',2019,09,345678);   
insert into tbl values ('test1',2019,10,567890);   
insert into tbl values ('test1',2019,11,123456);   
insert into tbl values ('test1',2019,12,234567);   
insert into tbl values ('test2',2019,11,12);   
insert into tbl values ('test2',2019,12,23);
insert into tbl select * from tbl;

–行转列

bill=# select   
bill-#  js-'seller' as seller,    
bill-#  js-'se_year' as se_year,   
bill-#  jan ,  
bill-#  feb ,  
bill-#  mar ,  
bill-#  apr ,  
bill-#  may ,  
bill-#  jun ,  
bill-#  jul ,  
bill-#  aug ,  
bill-#  sep ,  
bill-#  oct ,  
bill-#  nov ,  
bill-#  dec   
bill-# from crosstab(  
bill(#  -- 这个是需要进行行列变换的源SQL ， 数据源。  
bill(#  -- 排序字段为group by字段 ，最后一个字段为转换后的内容字段，导数第二个字段为行列变换的字段（内容为枚举，比如月份）  
bill(#  -- （必须在下一个参数中提取出对应的所有枚举值）  
bill(#  $$select jsonb_build_object('seller', seller, 'se_year', se_year) as js, se_month, sum(se_amount) from tbl group by 1,2 order by 1$$,    
bill(#  -- 行列转换的行，有哪些值被提取出来作为列。 这个在这里代表的是月份，也就是se_month的值   
bill(#  -- 或(select * from (values('jan'),...('dec')) t(se_month))  
bill(#  'select distinct se_month from tbl order by 1'     
bill(# )   
bill-# as  -- crosstab 输出格式  
bill-# ( js jsonb, -- 第一个参数SQL内对应的order by对应的字段（1个或多个）  
bill(#  Jan numeric, -- 第一个参数SQL内对应导数第二个字段的枚举值，（行转列）  
bill(#  feb numeric, -- ...同上  
bill(#  mar numeric,  
bill(#  apr numeric,  
bill(#  may numeric,  
bill(#  jun numeric,  
bill(#  jul numeric,  
bill(#  aug numeric,  
bill(#  sep numeric,  
bill(#  oct numeric,  
bill(#  nov numeric,  
bill(#  dec numeric  
bill(# )   
bill-# order by 1,2;  
 seller | se_year | jan  | feb  | mar  | apr  |  may  | jun  | jul  | aug  | sep  |  oct  | nov  | dec  
--------+---------+--------+--------+--------+--------+---------+--------+--------+--------+--------+---------+--------+--------
 test1 | 2019  | 246912 | 469134 | 691356 | 691356 | 1135780 | 246912 | 469134 | 691356 | 691356 | 1135780 | 246912 | 469134
 test1 | 2020  | 246912 | 469134 | 691356 | 691356 | 1135780 |    |    |    |    |     |    |    
 test2 | 2019  |    |    |    |    |     |    |    |    |    |     |   24 |   46
 test2 | 2020  |   24 |   46 |   68 |   90 |   112 |    |    |    |    |     |    |    
 test3 | 2020  |    |    |   24 |   90 |   112 |    |    |    |    |     |    |    
 test4 | 2020  |    |   40 |   60 |   80 |   100 |    |    |    |    |     |    |    
(6 rows)

–列转行

bill=# with a as ( -- A对应原始数据（即需要列转行的数据） 
bill(# select   
bill(#  js-'seller' as seller,    
bill(#  js-'se_year' as se_year,   
bill(#  jan ,  
bill(#  feb ,  
bill(#  mar ,  
bill(#  apr ,  
bill(#  may ,  
bill(#  jun ,  
bill(#  jul ,  
bill(#  aug ,  
bill(#  sep ,  
bill(#  oct ,  
bill(#  nov ,  
bill(#  dec   
bill(# from crosstab(  
bill(#  -- 这个是需要进行行列变换的源SQL ， 数据源。  
bill(#  -- 排序字段为group by字段 ，最后一个字段为转换后的内容字段，导数第二个字段为行列变换的字段（内容为枚举，比如月份）  
bill(#  -- （必须在下一个参数中提取出对应的所有枚举值）  
bill(#  $$select jsonb_build_object('seller', seller, 'se_year', se_year) as js, se_month, sum(se_amount) from tbl group by 1,2 order by 1$$,    
bill(#  -- 行列转换的行，有哪些值被提取出来作为列。 这个在这里代表的是月份，也就是se_month的值   
bill(#  -- 或(select * from (values('jan'),...('dec')) t(se_month))  
bill(#  'select distinct se_month from tbl order by 1'     
bill(# )   
bill(# as  -- crosstab 输出格式  
bill(# ( js jsonb, -- 第一个参数SQL内对应的order by对应的字段（1个或多个）  
bill(#  Jan numeric, -- 第一个参数SQL内对应导数第二个字段的枚举值，（行转列）  
bill(#  feb numeric, -- ...同上  
bill(#  mar numeric,  
bill(#  apr numeric,  
bill(#  may numeric,  
bill(#  jun numeric,  
bill(#  jul numeric,  
bill(#  aug numeric,  
bill(#  sep numeric,  
bill(#  oct numeric,  
bill(#  nov numeric,  
bill(#  dec numeric  
bill(# )   
bill(# order by 1,2  
bill(# )  
bill-# ,   
bill-# -- b ， 用jsonb把多列合并为一列，并使用jsonb_each展开。 
bill-# b as (select seller, se_year, jsonb_each(row_to_json(a)::jsonb-'seller'::text-'se_year'::text) as rec from a)   
bill-# select seller, se_year, (b.rec).key as month, (b.rec).value as sum from b;  
 seller | se_year | month |  sum  
--------+---------+-------+---------
 test1 | 2019  | apr  | 691356
 test1 | 2019  | aug  | 691356
 test1 | 2019  | dec  | 469134
 test1 | 2019  | feb  | 469134
 test1 | 2019  | jan  | 246912
 test1 | 2019  | jul  | 469134
 test1 | 2019  | jun  | 246912
 test1 | 2019  | mar  | 691356
 test1 | 2019  | may  | 1135780
 test1 | 2019  | nov  | 246912
 test1 | 2019  | oct  | 1135780
 test1 | 2019  | sep  | 691356
 test1 | 2020  | apr  | 691356
 test1 | 2020  | aug  | null
 test1 | 2020  | dec  | null
 test1 | 2020  | feb  | 469134
 test1 | 2020  | jan  | 246912
 test1 | 2020  | jul  | null
 test1 | 2020  | jun  | null
 test1 | 2020  | mar  | 691356
 test1 | 2020  | may  | 1135780
 test1 | 2020  | nov  | null
 test1 | 2020  | oct  | null
 test1 | 2020  | sep  | null
 test2 | 2019  | apr  | null
 test2 | 2019  | aug  | null
 test2 | 2019  | dec  | 46
 test2 | 2019  | feb  | null
 test2 | 2019  | jan  | null
 test2 | 2019  | jul  | null
 test2 | 2019  | jun  | null
 test2 | 2019  | mar  | null
 test2 | 2019  | may  | null
 test2 | 2019  | nov  | 24
 test2 | 2019  | oct  | null
 test2 | 2019  | sep  | null
 test2 | 2020  | apr  | 90
 test2 | 2020  | aug  | null
 test2 | 2020  | dec  | null
 test2 | 2020  | feb  | 46
 test2 | 2020  | jan  | 24
 test2 | 2020  | jul  | null
 test2 | 2020  | jun  | null
 test2 | 2020  | mar  | 68
 test2 | 2020  | may  | 112
 test2 | 2020  | nov  | null
 test2 | 2020  | oct  | null
 test2 | 2020  | sep  | null
 test3 | 2020  | apr  | 90
 test3 | 2020  | aug  | null
 test3 | 2020  | dec  | null
 test3 | 2020  | feb  | null
 test3 | 2020  | jan  | null
 test3 | 2020  | jul  | null
 test3 | 2020  | jun  | null
 test3 | 2020  | mar  | 24
 test3 | 2020  | may  | 112
 test3 | 2020  | nov  | null
 test3 | 2020  | oct  | null
 test3 | 2020  | sep  | null
 test4 | 2020  | apr  | 80
 test4 | 2020  | aug  | null
 test4 | 2020  | dec  | null
 test4 | 2020  | feb  | 40
 test4 | 2020  | jan  | null
 test4 | 2020  | jul  | null
 test4 | 2020  | jun  | null
 test4 | 2020  | mar  | 60
 test4 | 2020  | may  | 100
 test4 | 2020  | nov  | null
 test4 | 2020  | oct  | null
 test4 | 2020  | sep  | null
(72 rows)

以上为个人经验，希望能给大家一个参考，也希望大家多多支持。如有错误或未考虑完全的地方，望不吝赐教。

上一篇：postgresql安装及配置超详细教程
下一篇：Docker环境下升级PostgreSQL的步骤方法详解