Learn SQL the right way - session 3 | Primary Key vs Unique Key | Trendytech

[@sumitmittal07]

Checkout the Big Data course details here: trendytech.in/?referrer=youtube_sql4

[@SANATANIAMERICA]

I have been working as a QA automation engineer. would like to update my skill/competency. which course do you suggest for me sir?

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[@Soham_III]

I have watched a lot off tutorial on udemy and youtube no one teach like you sir. Your teaching is simple and understandable thanx a lot sir ❤❤

[@nikhilgupta6803]

waiting for the completion of basics and upcoming advanced concepts of sql sumit sir....excellent work n gift for working professionals.

[@sumitmittal07]

Thank you Nikhil for those kind words. Motivates me to create more :)

[@nikhilgupta6803]

@@sumitmittal07 🙏

[@dineshchavan9462]

Beyond the ordinary..No words to describe your teaching..it is flawless..

[@sumitmittal07]

humbled 😀

[@pankajmaheshwari128]

It is rare to find such easy and descriptive session .My suggestion is to go through complete playlist practice along side . It will take some time but trust it will worth it. I am one of student of Sumit sir's big data program. The way he explain the concept is just phenomenal. Thanks Sumit sir :)

[@narenderreddynarender8970]

Hello Sumit. Thank you for providing valuable course in tough times. I've followed few channels for SQL and it's always confusing because lot of other flavours of SQL are mixed with it. Hopefully I'll find out complete SQL course and be able to write easy to intermediate queries required for Data Analyst. Thank you again and very good luck to all the viewer's and subscribers of this course 👍🙏🙂

[@yogeshkumarkumawat]

Amazing SQL videos.. finally i have found good channel for SQL

[@sumitmittal07]

Glad to hear that!

[@dlakhaiyar]

Sumit Sir makes everything simple, he is a true magician. Thank you so much Sir for the SQL couse, I am loving it! ❤️

[@sumitmittal07]

Pleased that you are liking the SQL series :)

[@PriyankaBhatt-m7o]

It is really a very good course. I am learning SQL from your videos and I am loving it. Thank you.

[@rokibchi]

Well described, My 2nd Day of this learning session.

[@ksktest187]

Hi Sir, an amazing journey, I am starting it to sharpen my skills in SQL, without you it wouldn't have possible. Hats of for you Sir.

[@atigyamishra4894]

Really appreciate your way of teaching sir . Clarity is on next level . Many thanks for your complete SQL play list .

[@asifbhat3796]

This is the way of teaching

[@saurabhtekale5084]

Wonderful lession sir ...looking forward to go deeper into SQL🙂

[@sumitmittal07]

Keep following, you will master SQL the right way :)

[@Oisimran]

Spark-Sumit Forever😁

[@charansai235]

so far the session are upto point, very easy to understand - good work sumit sir 👏

[@kvmadhu13]

Sir, your way of teaching is amazing.

[@abhishekkumar-sj2jj]

thank you for the quality course SUMIT SIR

[@akshay8756]

13:45 autoincrement is irrespective of primary key right ? good candidate i didnt get 🤔

[@tushardesai644]

Excellent teaching Sumit Sir.

[@sumitmittal07]

Happy to know that you are enjoying my teaching :)

[@yashdhas8202]

Excited for 4th Video

[@jyothia2177]

You are doing an excellent work sir. Keep it up.

[@fitking1234]

Amazing Lecture

[@saqibtariq3909]

Thankyou Sumit Sir ! Nice tutorials 🙂

[@akp7-7]

sir when primary key is set auto-increment for id and we have a unique key for name ..why for each wrong value for unique key ..the primary key auto increment it self? like my id=1 if i give unique key two times wrong .then 3rd time i gave correct value as per unique key..now my id=4..why not id=2 or 3 because value was not inserted in db and they were wrong as per unique key.

[@SoumyaChatterjee-o7t]

@Sumit Sir: If you can share the commands & class notes in the description section that would be really great.

[@CricketLivejavwad]

Sir kar diya subscribe :)

[@purnenduduttajha7244]

Amazing ❤🔥

[@abhijeetsondkar3593]

Hi Sumit sir, can you please help with the names of other DB's where multiple null values are not allowed for Unique Key constraint?

[@saurabhdhyani4498]

Great video SIr!

[@kaneezfatimakhan9692]

Thanks sumit ! Good job 👍

[@kiran4608]

Thank you sir🙌

[@sumitmittal07]

Most welcome

[@lakshminarayanavanapalli6769]

Hello sir.....do we have a concept of composite unique key??

[@naga4326]

Hey Sumit can you pls procedures, views, and triggers

[@pawanseth70]

You are the best

[@navneet2649]

Sir can u give real life scenarios in which only Primary Key can/should be used and in situations where only Unique Key can/should be used? and thanks for the video 👍👍💖💖

[@akashshirale1927]

If we make the unique key as not null as well, will it behave like primary key?

[@VinaySingh-op1el]

Thank you so much sir

[@moyeenshaikh9915]

sir combination of unique keys means the same thing as putting the unique key in from of column name?

[@vishnuvardhanyerasi]

Sir can you also please do the videos of plsql course please

[@viratsharma5830]

When you use auto increment the structure of a table was showing thats the primary key is also active but you are using auto increment how both of them can be use at the same time.

[@sameerpandey2344]

Fall in love with learning SQL

[@richathakur7715]

Hi Sumit, i have started this course can you please tell shortcut to paste the code from notepad to the groomIDE workspace as ctrl+V does not work.

[@hasanmougharbel8030]

Hey there, kudos to your great efforts. I have a simple enquiry as an newbie sql learner. Why cant i have more than one primary key in a single table? Thanks for taking care of this.

[@Naveen-qz1rv]

Basically its like a roll number of a student.. you can have multiple keys which can uniquely identify records, bt those keys will be candidate key.. one key among them will be chosen as primary key for the table.. And yes, a table xan only have one and only primary key.. they key can be combo of multiple columns, but ony one primary key can exist

[@chandannandy809]

excellent

[@hareramrai4190]

Hello Sir, Good day. Sir , You mentioned about in session 1 you will provide this notepad where you are writing . But this is the 3rd video but i am not able to find any link related about this note. if you will provide it will very helpful for us.. Thank you Sir:)

[@vaibhavdeodhar3301]

Hi Sumit sir, From where I can download notes for these seasions

[@RahulKumar-io1fw]

Sir Can we get your notes for sql series it is reallly very helpful

[@amazingriknow5986]

Dont waste money on paid lectures. Trust me , this sql series is better than almost 99.9% of paid lectures.

[@AdityaSharma-xh8tg]

Sir, based on below screen shot here if ID is unique key, then does that mean records 2 and 3 are different, since Null means (we do not know the value) hence records 2 and 3 are distinct? even though they look same, but the records are unique Please advise..

[@avinash9291]

Sir, Auto_increment dint work alone, i had to add Primary Key to it

[@mandakinigiri7493]

While explaining about unique key , As you said we can have one primary key But in composite primary key you used two columns as primary key i.e PRIMARY KEY (ID, NAME) Then how it is possible ? THEN

[@Venom-yk3wu]

bt u added two primary keys in the table ? when u said we can add only 1

[@ahomosapienforlife5902]

If unique key allow NULL values but if table definition has NOT NULL constraint then would NULL be accepted??

[@sa2742]

Thx

[@niteshadwani8522]

where i can find this notes

[@PiyushAtghara]

I am a working professional and loved your teaching methodology. Is there a way to get the running notes you are creating during the videos? @Trendytech Insights

[@jimitshah7636]

What is a real life example where a unique key can be used?

[@fawadzaadi]

Hello Sir, Can we auto-increment Unique Keys?

[@shreyanshsingh2782]

yes we can have it , but no meaning to do as we do it for primary key just to ensure if we have duplicate records then also we can distingiush between them.

[@rahulkale3984]

For Auto Increment key Default it would take 1,2,.... For 1101,1102,.... how can we get this ID's in auto increment. Sumit Sir Could pls tell us ?

[@SAURABHKUMAR-nn8sl]

Insert the first record with id 1101 explicitly eg: INSERT INTO employee(id, fn, ln, age) VALUES (1101, '.....', ....... ); Then insert normally, no need to specify id in columns, it will auto-increment. eg: INSERT INTO employee(fn, ln, age) VALUES ..... ;

[@kamilmohammed9722]

Why u r dropping table, can't we use alter /update table?

[@sumitmittal07]

We can definitely use alter as seen in session 4... However Update is to update the record but not the structure.

[@swarajkumar9550]

when I create table in this format and then describe the table it shows id as primary key although I have specified it as UNIQUE KEY, if you could please tell the reason behind this.. create table employee ( id int UNIQUE KEY AUTO_INCREMENT, firstname varchar(20), lastname varchar(20), age int NOT NULL );

[@swarajkumar9550]

if this happened because of the auto increment then what if want to use auto increment with unique key.

[@amreishpadmaraju2749]

@@swarajkumar9550 create table employee ( id int AUTO_INCREMENT, firstname varchar(20), lastname varchar(20), age int NOT NULL, UNIQUE KEY (id) );

[@AdityaSharma-xh8tg]

Hi Sir, Thank you very much for this video, I have a question here which others might have as well: Primary key (FirstName,LastName) is this same as FirstName varchar(20) Primary Key, LastName Varchar(20) PrimaryKey, will the sql editor accept the second statement? Since you said there is only one Primary key but we can have combination of 2 columns as Primary Key? Looking at the schema if there are more than 1 column with Primary key, should we say that Primary key was imposed on the combination of those columns?

[@Pvamsikg]

Hi Aditya , have you got the answer for it, if please can you replay it! thanks

[@shreyanshsingh2782]

hey they are not same PRIMARY KEY(...) will work but second one will not work you can try maybe because if we give it for seperate columns, then this statement will be wrong like we can have only one primary key

[@sandeepdvn9275]

spr

[@nukallakarthik9926]

Where is the notepad document sir

[@piyushjani8141]

Sumit sir ye document provide kardo please

[@harishboddula9639]

[@SachinSharma-yd1ck]

Hi Sumit sir, I cannot connect to your LinkedIn account. Please provide a link so that I can connect to you. I need some help so want to get in touch with you. Thanks in advance!