PostgreSQL 9.3: STUFF and CHARINDEX function

Question

I want to retrieve some part of given string.

Here is the following example for the string:

Example: In SQL Server

Declare @Names varchar = 'H1,H2,H3,'

SELECT STUFF(@Names,1,CHARINDEX(',',@Names,0),'');

After referring this : 'stuff' and 'for xml path('')' from SQL Server in Postgresql.

String_agg can't help me for this scenario.

Answer 1

You are looking for equivalent TSQL function of STUFF in PostgrSQL which i think is: overlay

so for example:

SELECT STUFF('abcdef', 2, 3, 'ijklmn');

and

select overlay('abcdef' placing 'ijklmn' from 2 for 3)

give both the same result which is;

'aijklmnef'

in other words:

They inserts a string into another string. It deletes a specified length of characters in the 
first string at the start position and then inserts the second string into the first string at 
the start position.