LPAD without trimming in mysql

I am trying to find a way to add 0 at the beginning of an ID without trimming it :

I am currently using LPAD(id,4,"0") witch works fine until 9999

• Request : SELECT LPAD(12345,4,"0");
• Excepted result : 12345
• Result : 1234

I am Looking for a Request who does LPAD(id, MAX(LENGTH(id),4), "0")

I found SELECT IF(LENGTH(12345)>4, 12345, LPAD(12345, 4, "0")); but i would prefer if the 4 was in a single place (to make it easier use it elsewhere).

• Is there a build-in function that does what i'm looking For ?
• Or is there an alternative to the function MAX() that would work in that situation ?
• Or should I stick with the IF(LENGTH) solution and it's drawbacks ?

Edit :

ZEROFILL doesn't fit my needs because I also need the id without 0s. I mainly use the ID without the LPAD(), but when I do, I use it with a prefix : CONCAT("PFX", LPAD(id,4,"0"))

Thanks for your Help

PS: please tell me if i do anything wrong, it's my first time asking here.