Last week on my Facebook Page, I have received a couple message about what is a similar solution of SQL Server STUFF () in PostgreSQL.

Most of the Database Developers require to perform String Aggregation based on different group of records.

Since PostgreSQL 9.0, STRING_AGG(expression, delimiter) function is available to perform String Aggregation operation.
Using STRING_AGG(), We can concatenate strings using different type of delimiter symbols.

Example of STRING_AGG():

Create a sample Students table:

CREATE TABLE tbl_Students
(
	StudID INT 
	,StudName CHARACTER VARYING
	,StudGrades CHAR(1)
);

Insert few sample records:

INSERT INTO tbl_Students 
VALUES 
(1,'Anvesh','A'),(2,'Kimly','B')
,(3,'Jenny','C'),(4,'Ali','B')
,(5,'Mukesh','D'),(6,'Sofia','A')
,(7,'Roy','C'),(8,'Martin','C');

Concatenate Students Name per each Student Grade and arrange by Grade wise row (Using STRING_AGG()):

SELECT 	
	StudGrades
	,STRING_AGG(StudName,', ') AS StudPerGrade
FROM tbl_Students
GROUP BY StudGrades
ORDER BY 1 ;

The Result:

studgrades |    studpergrade
------------+--------------------
 A          | Anvesh, Sofia
 B          | Kimly, Ali
 C          | Jenny, Roy, Martin
 D          | Mukesh
(4 rows)