Primary Key vs Unique Key in SQL Explained in 60 Seconds! #TechWithGitanjali

Added: 2026-05-16

[00:00:00]First question, difference in primary key versus unique key. I give me the like real time example. Yeah, like we are using primary key, where we are using unique key. Yes, go ahead, please.

[00:00:08]So, primary key is not null and it uh does not allow duplicate values. And unique key can allow null and it can and the values should not be duplicate.

[00:00:18]Primary key is something that uh uniquely identifies the data record, but unique key is is something that does not really identify the unique record. It is just unique in the record and it can be null.

[00:00:30]Correct.

[00:00:30]>> Next is primary key supports auto increment, but unique key does not supports auto increment. There can be only one primary key in a table, but there can be multiple unique keys in a table. And uh real time use case of primary key and unique key is that if you have a database of employee database of any company, on first day when you join, EMP ID is the thing that is mandatorily generated and it cannot be left null or empty. So, other field other unique fields like contact, email or PAN card, Aadhaar card, they can be null, but it does not uniquely identify the record. EMP ID is something that is unique to each candidate. So, it cannot be left null. Correct. Great.

[00:01:10]>> [music]