Merge Multiple Rows with Same Id into One Row

Pandas | merge rows with same id

Use

• DataFrame.groupby - Group DataFrame or Series using a mapper or by a Series of columns.
• .groupby.GroupBy.last - Compute last of group values.
• DataFrame.replace - Replace values given in to_replace with value.

Ex.

df = df.replace('',np.nan, regex=True)
df1 = df.groupby('id',as_index=False,sort=False).last()
print(df1)

   id firstname lastname              email  updatedate
0  A1     wendy    smith     smith@mail.com  2019-02-03
1  A2     harry     lynn  harylynn@mail.com  2019-03-12
2  A3     tinna   dickey     tinna@mail.com  2013-06-12
3  A4       Tom      Lee       Tom@mail.com  2012-06-12
4  A5      Ella      NaN      Ella@mail.com  2019-07-12
5  A6       Ben     Lang       Ben@mail.com  2019-03-12

How to concatenate many rows with same id in sql?

In SQL-Server you can do it in the following:

QUERY

SELECT id, displayname = 
    STUFF((SELECT DISTINCT ', ' + displayname
           FROM #t b 
           WHERE b.id = a.id 
          FOR XML PATH('')), 1, 2, '')
FROM #t a
GROUP BY id

TEST DATA

create table #t 
(
id int,
displayname nvarchar(max)
)

insert into #t values    
 (1 ,'Editor')
,(1 ,'Reviewer')
,(7 ,'EIC')
,(7 ,'Editor')
,(7 ,'Reviewer')
,(7 ,'Editor')
,(19,'EIC')
,(19,'Editor')
,(19,'Reviewer')

OUTPUT

id  displayname
1   Editor, Reviewer
7   Editor, EIC, Reviewer
19  Editor, EIC, Reviewer

MYSQL how to merge rows with same field id into a single row

GROUP_CONCAT supports DISTINCT and SEPARATOR``

CREATE TABLE table1 (
  `rowid` VARCHAR(139),
  `title` VARCHAR(139),
  `author_f_name` VARCHAR(139),
  `author_m_name` VARCHAR(139),
  `author_l_name` VARCHAR(139),
  `coauthor_first_name` VARCHAR(139),
  `coauthor_middle_name` VARCHAR(139),
  `coauthor_last_name` VARCHAR(139)
);

INSERT INTO table1
  (`rowid`, `title`, `author_f_name`, `author_m_name`, `author_l_name`, `coauthor_first_name`, `coauthor_middle_name`, `coauthor_last_name`)
VALUES
  ('1.',   'Blog Title.',       'Roy',                  NULL,                   'Thomas.',               'Joe',                   'Shann',               'Mathews'),
  ('1.',   'Blog Title.',       'Thomas',                  'NULL',              'Edison',            'Kunal',               NULL,                       'Shar');

SELECT 
`rowid`
, GROUP_CONCAT(DISTINCT `title`  SEPARATOR ' |||') tilte
, GROUP_CONCAT(DISTINCT `author_f_name` SEPARATOR ' |||') author_f_name
, GROUP_CONCAT(DISTINCT `author_m_name` SEPARATOR ' |||') author_m_name
, GROUP_CONCAT(DISTINCT `author_l_name` SEPARATOR ' |||') author_l_name
, GROUP_CONCAT(DISTINCT `coauthor_first_name` SEPARATOR ' |||') coauthor_first_name
, GROUP_CONCAT(DISTINCT `coauthor_middle_name` SEPARATOR ' |||') coauthor_middle_name
, GROUP_CONCAT(DISTINCT `coauthor_last_name` SEPARATOR ' |||') coauthor_last_name
FROM table1
GROUP BY `rowid`

rowid | tilte       | author_f_name | author_m_name | author_l_name     | coauthor_first_name | coauthor_middle_name | coauthor_last_name
:---- | :---------- | :------------ | :------------ | :---------------- | :------------------ | :------------------- | :-----------------
1.    | Blog Title. | Roy |||Thomas | NULL          | Edison |||Thomas. | Joe |||Kunal        | Shann                | Mathews |||Shar   

db<>fiddle here

SELECT 
`rowid`
, GROUP_CONCAT(DISTINCT `title`  SEPARATOR ' |||') tilte
, GROUP_CONCAT(DISTINCT CONCAT(`author_f_name`,' ',COALESCE(`author_m_name`,''),' ',`author_l_name`) SEPARATOR ' |||') author_full_name
, GROUP_CONCAT(DISTINCT CONCAT(`coauthor_first_name`,' ',COALESCE(`coauthor_middle_name`,''),' ',`coauthor_last_name`) SEPARATOR ' |||') coauthor_full_name
FROM table1
GROUP BY `rowid`

rowid | tilte       | author_full_name                   | coauthor_full_name              
:---- | :---------- | :--------------------------------- | :-------------------------------
1.    | Blog Title. | Roy  Thomas. |||Thomas NULL Edison | Joe Shann Mathews |||Kunal  Shar

db<>fiddle here

Same ID with multiple records to single row

If you just want to view the output suggested in table B using table A, then use a pivot query:

SELECT
    source,
    ID,
    1 AS Type_1_ID
    MAX(CASE WHEN Type_ID = 1 THEN Error_info END) AS Error_info_1,
    2 AS Type_2_ID,
    MAX(CASE WHEN Type_ID = 2 THEN Error_info END) AS Error_info_2
FROM yourTable
GROUP BY
    source,
    ID;

R: Combine rows with same ID

Something like this:
Here we first group for all except the Var variables, then we use summarise(across... as suggested by @Limey in the comments section.
Main feature is to use na.rm=TRUE:

library(dplyr)

df %>% 
  group_by(ID, Date, N_Date, type) %>% 
  summarise(across(starts_with("Var"), ~sum(., na.rm = TRUE)))

     ID Date   N_Date type    Var1  Var2  Var3  Var4
  <int> <chr>   <int> <chr>  <int> <int> <int> <int>
1     1 4.7.22  50000 normal    12    23     5    54
2     2 4.7.22   4000 normal     0     2     0     0
3     3 5.7.22  20000 normal     7     0     0     0

Combine two rows in a single row with the same ID name

A simple aggregation should do the trick

Example

Select ID
      ,ID1 = max(ID1)
      ,ID2 = max(ID2)
      ,ID3 = max(ID3)
 From  YourTable
 Group By ID

Merge multiple rows (with same ID) into one?

I believe this will work (I tested it on an Oracle 11g, not a Teradata):

SELECT *
  FROM (SELECT id_nbr AS ID,
               contact_type AS contype,
               contact_first_name AS firstName,
               contact_last_name AS lastName,
               contact_phone_number AS phoneNumber,
               contact_address AS address,
               contact_email AS email
          FROM database.account_info
         WHERE contact_type in ('AAA', 'BBB', 'CCC')
        )
 PIVOT (max(firstName) AS firstName,
        max(lastName) AS lastName,
        max(phoneNumber) AS phone,
        max(email) AS email,
        max(address) AS address
   FOR contype IN ('AAA', 'BBB', 'CCC')
        )

The last line may require an alias, one of:

        ) AS derived_pivot
        ) derived_pivot

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