PadLeft function in T-SQL

Question

I have the following table A:

id
----
1
2
12
123
1234

I need to left-pad the id values with zero\'s:

id
----
0         


        

Answer 1

This works for strings, integers and numeric:

SELECT CONCAT(REPLICATE('0', 4 - LEN(id)), id)

Where 4 is desired length. Works for numbers with more than 4 digits, returns empty string on NULL value.