How do I remove the first characters of a specific column in a table?

SELECT RIGHT(MyColumn, LEN(MyColumn) - 4) AS MyTrimmedColumn

Edit: To explain, RIGHT takes 2 arguments - the string (or column) to operate on, and the number of characters to return (starting at the "right" side of the string). LEN returns the length of the column data, and we subtract four so that our RIGHT function leaves the leftmost 4 characters "behind".

Hope this makes sense.

Edit again - I just read Andrew's response, and he may very well have interperpereted correctly, and I might be mistaken. If this is the case (and you want to UPDATE the table rather than just return doctored results), you can do this:

UPDATE MyTable
SET MyColumn = RIGHT(MyColumn, LEN(MyColumn) - 4)

He's on the right track, but his solution will keep the 4 characters at the start of the string, rather than discarding said 4 characters.

Why use LEN so you have 2 string functions? All you need is character 5 on...

...SUBSTRING (Code1, 5, 8000)...

Try this:

update table YourTable
set YourField = substring(YourField, 5, len(YourField)-3);

Here's a simple mock-up of what you're trying to do :)

CREATE TABLE Codes
(
code1 varchar(10),
code2 varchar(10)
)

INSERT INTO Codes (CODE1, CODE2) vALUES ('ABCD1234','')


UPDATE Codes
SET code2 = SUBSTRING(Code1, 5, LEN(CODE1) -4)

So, use the last statement against the field you want to trim :)

The SUBSTRING function trims down Code1, starting at the FIFTH character, and continuing for the length of CODE1 less 4 (the number of characters skipped at the start).

The top answer is not suitable when values may have length less than 4.

In T-SQL

You will get "Invalid length parameter passed to the right function" because it doesn't accept negatives. Use a CASE statement:

SELECT case when len(foo) >= 4 then RIGHT(foo, LEN(foo) - 4) else '' end AS myfoo from mytable;

In Postgres

Values less than 4 give the surprising behavior below instead of an error, because passing negative values to RIGHT trims the first characters instead of the entire string. It makes more sense to use RIGHT(MyColumn, -5) instead.

An example comparing what you get when you use the top answer's "length - 5" instead of "-5":

create temp table foo (foo) as values ('123456789'),('12345678'),('1234567'),('123456'),('12345'),('1234'),('123'),('12'),('1'), ('');

select foo, right(foo, length(foo) - 5), right(foo, -5) from foo;

foo       len(foo) - 5  just -5   
--------- ------------  -------     
123456789 6789          6789 
12345678  678           678  
1234567   67            67   
123456    6             6    
12345                       
1234      234               
123       3                 
12                          
1