SQL Query to Concatenate Column Values from Multiple Rows in Oracle

SQL Query to concatenate column values from multiple rows in Oracle

There are a few ways depending on what version you have - see the oracle documentation on string aggregation techniques. A very common one is to use LISTAGG:

SELECT pid, LISTAGG(Desc, ' ') WITHIN GROUP (ORDER BY seq) AS description
FROM B GROUP BY pid;

Then join to A to pick out the pids you want.

Note: Out of the box, LISTAGG only works correctly with VARCHAR2 columns.

concatenate column values from multiple rows in Oracle without duplicates

One option would be using regexp_replace():

select regexp_replace(
                      listagg( t.id,',') within group (order by t.id)
                      , '([^,]+)(,\1)+', '\1') as "Result"
  from t

Demo

Oracle - SQL to concatenate multiple rows

If you have Oracle 11g you could use the LISTAGG() function for this:

SELECT
      id
    , listagg(str) WITHIN GROUP (ORDER BY OFFSET) AS str_of_str
FROM yourtable
GROUP BY id

see: http://docs.oracle.com/cd/E11882_01/server.112/e10592/functions089.htm
and this sqlfiddle

  | ID |               STR_OF_STR |
    |----|--------------------------|
    |  1 | TestSTR1TestSTR3TestSTR5 |
    |  2 |         TestSTR4TestSTR2 |
    |  3 |                 TestSTR6 |

Concatenate across columns and rows using group and listagg in Oracle SQL

Use the following query where you will directly get concatenated column values:

SELECT
    "GROUP",
    LISTAGG(VAL_1 || VAL_2 || VAL_3)  
        WITHIN GROUP(ORDER BY VAL_1) AS "TEXT"
FROM DATA
GROUP BY "GROUP";

Note: Do not use oracle reserved keywords as the column names. Here GROUP is the oracle reserved keyword.

Cheers!!

How can multiple rows be concatenated into one in Oracle without creating a stored procedure?

There are many way to do the string aggregation, but the easiest is a user defined function. Try this for a way that does not require a function. As a note, there is no simple way without the function.

This is the shortest route without a custom function: (it uses the ROW_NUMBER() and SYS_CONNECT_BY_PATH functions )

SELECT questionid,
       LTRIM(MAX(SYS_CONNECT_BY_PATH(elementid,','))
       KEEP (DENSE_RANK LAST ORDER BY curr),',') AS elements
FROM   (SELECT questionid,
               elementid,
               ROW_NUMBER() OVER (PARTITION BY questionid ORDER BY elementid) AS curr,
               ROW_NUMBER() OVER (PARTITION BY questionid ORDER BY elementid) -1 AS prev
        FROM   emp)
GROUP BY questionid
CONNECT BY prev = PRIOR curr AND questionid = PRIOR questionid
START WITH curr = 1;

Concatenate and group multiple rows in Oracle

Consider using LISTAGG function in case you're on 11g:

select grp, listagg(name,',') within group( order by name ) 
  from name_table group by grp

sqlFiddle

upd: In case you're not, consider using analytics:

select grp,
    ltrim(max(sys_connect_by_path
       (name, ',' )), ',')
        scbp
  from (select name, grp,
            row_number() over
           (partition by grp
            order by name) rn
         from tab
          )
start with rn = 1
connect by prior rn = rn-1
and prior grp = grp
  group by grp
  order by grp

sqlFiddle

How can I combine multiple rows into a comma-delimited list in Oracle?

Here is a simple way without stragg or creating a function.

create table countries ( country_name varchar2 (100));

insert into countries values ('Albania');

insert into countries values ('Andorra');

insert into countries values ('Antigua');


SELECT SUBSTR (SYS_CONNECT_BY_PATH (country_name , ','), 2) csv
      FROM (SELECT country_name , ROW_NUMBER () OVER (ORDER BY country_name ) rn,
                   COUNT (*) OVER () cnt
              FROM countries)
     WHERE rn = cnt
START WITH rn = 1
CONNECT BY rn = PRIOR rn + 1;

CSV                                                                             
--------------------------
Albania,Andorra,Antigua                                                         

1 row selected.

As others have mentioned, if you are on 11g R2 or greater, you can now use listagg which is much simpler.

select listagg(country_name,', ') within group(order by country_name) csv
  from countries;

CSV                                                                             
--------------------------
Albania, Andorra, Antigua

1 row selected.

How to concatenate text from multiple rows into a single text string in SQL Server

If you are on SQL Server 2017 or Azure, see Mathieu Renda answer.

I had a similar issue when I was trying to join two tables with one-to-many relationships. In SQL 2005 I found that XML PATH method can handle the concatenation of the rows very easily.

If there is a table called STUDENTS

SubjectID       StudentName
----------      -------------
1               Mary
1               John
1               Sam
2               Alaina
2               Edward

Result I expected was:

SubjectID       StudentName
----------      -------------
1               Mary, John, Sam
2               Alaina, Edward

I used the following T-SQL:

SELECT Main.SubjectID,
       LEFT(Main.Students,Len(Main.Students)-1) As "Students"
FROM
    (
        SELECT DISTINCT ST2.SubjectID, 
            (
                SELECT ST1.StudentName + ',' AS [text()]
                FROM dbo.Students ST1
                WHERE ST1.SubjectID = ST2.SubjectID
                ORDER BY ST1.SubjectID
                FOR XML PATH (''), TYPE
            ).value('text()[1]','nvarchar(max)') [Students]
        FROM dbo.Students ST2
    ) [Main]

You can do the same thing in a more compact way if you can concat the commas at the beginning and use substring to skip the first one so you don't need to do a sub-query:

SELECT DISTINCT ST2.SubjectID, 
    SUBSTRING(
        (
            SELECT ','+ST1.StudentName  AS [text()]
            FROM dbo.Students ST1
            WHERE ST1.SubjectID = ST2.SubjectID
            ORDER BY ST1.SubjectID
            FOR XML PATH (''), TYPE
        ).value('text()[1]','nvarchar(max)'), 2, 1000) [Students]
FROM dbo.Students ST2

How to group and concatenate results from multiple records?

You are looking for listagg():

select a.id, listagg(b.value, ',') within group (order by b.value)
from a left join
     b
     on a.name = b.name
where a.id = 12345
group by a.id;

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