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In this tutorial, we will see 3 methods to add leading zeros to number in sql.

Video timeline

00:00 Introduction
00:25 Problem Statement
01:20 First Method: to_char function
02:50 Second Method: case statement
04:05 Third Method: right function

SQL Queries used in the video:

/* using to_char function */
select catid,
to_char(catid,'0000') as catid_1
from category
order by 1 desc;

/* using case statement */
select catid,
case when length(catid)=1 then '000'||catid
when length(catid)=2 then '00'||catid
when length(catid)=3 then '0'||catid
when length(catid)=4 then ''||catid
end as catid_1
from category
order by 1 desc;

/* using right function */
select catid,
right('0000'||catid,4) as catid_1
from category
order by 1 desc;

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