Add String in a String before ".extention"? - sql

Question

I have a table like:
ID NAME
----------------
35 File.png
What I want to do is update that record as:
ID NAME
----------------
35 File_35.png
I have this:
DECLARE arch_cursor CURSOR FOR SELECT Id from dbo.Archivos WHERE Nombre LIKE ('%' + #Id_Relacion_Articulo_Archivo + '%')
OPEN contact_cursor;
FETCH NEXT FROM arch_cursor
INTO #Id_cur
WHILE(##FETCH_STATUS = 0 )
UPDATE dbo.Archivos SET Nombre ...
CLOSE arch_cursor;
DEALLOCATE arch_cursor;
I know that STUFF statement can do something like put a string on a specific place of the string, but somebody know how to specify "insert string before "." without losing the left chars too?"

Answer 1

select id
, concat(left(name, charindex('.', name)-1), '_', id, RIGHT(name,(CHARINDEX('.', name))-1)) NAME
from test
Here is a demo
Also you can do it with a replace:
select id
, replace(name, '.', concat('_',id,'.'))
from test
And here is the one option you can use if you will look from the right (first occurrence of the character '.'):
select id
, concat(substring(name, 1, len(name)-charindex('.', (reverse(name))))
, '_'
, id
, substring(name, len(name)-charindex('.', (reverse(name)))+1, charindex('.', (reverse(name)))))
from test
Here is a demo where you can see all 3 of this examples in action with this two rows of data:
insert into test values (35, 'File.png')
insert into test values (55,
'File.File.png')

Answer 2

If no files can have a . in the name (apart from to denote the extension) I find STUFF easiest for this:
SELECT ID, [Name],
STUFF([Name], CHARINDEX('.',[Name]),0,CONCAT('_',ID)) AS NewName
FROM (VALUES(35,'File.png'))V(ID,[Name]);
If there could be multiple . characters and it needs to prior to the last one, you have to use the (expensive) function REVERSE:*
SELECT ID, [Name],
STUFF([Name], LEN([Name]) - CHARINDEX('.',REVERSE([Name]))+1,0,CONCAT('_',ID)) AS NewName
FROM (VALUES(35,'File.png'),(36,'File.2.png'))V(ID,[Name])
Also, don't loop. Just do this in a set based method. You're using a RDBMS, not a Programming Language:
UPDATE dbo.YourTable
SET File = STUFF([Name], CHARINDEX('.',[Name]),0,CONCAT('_',ID));