Top 25 SQL Interview Questions and Answers(The BEST SQL Interview Questions)

[@priyankadevi-zl9jx]

techTFQ - the main difference between delete and truncate statements besides removing the data from the table, truncate resets the id to 0 whereas delete doesn't do that. let's say if a table has 100 records. if you use delete statement and delete all 100 records and try to insert a new record. Your new record will have the id starting from 101 whereas with truncate it will start from 1. I think this isn't on your differences. Basically, truncate removes the memory allocation along with the data whereas delete doesn't. Thanks!

[@honestreview4670]

you are right

[@maihuire11]

@@honestreview4670 That´s correct

[@igloo211]

Im in this field and I can tell you that typically the people that ask you these questions don’t know the answers until they looked them up to hit you with them during the interview

[@manikantashet5921]

exactly, many actually don't. they wouldn't even recognize other approaches used while solving questions. sadly thats what most candidates have to deal with.

[@gparvez6695]

You are right about this questions. My recent interview with one of the MNC in France asked few of this questions. here are the questions that I was asked. 1. Do you know window functions? Can you name few? 2. Have you ever used CTE table? 3. Diffrence btw where, Having , Group by.

[@techTFQ]

Thank you for sharing these parvez.. it’s good to know

[@TheVishalrockstar]

hi buddy can u help me to search good company

[@suneetha11697]

Thanks

[@DarrellWolfe]

What I have found fascinating about learning SQL is this: After doing a LOT of queries to the database with Microsoft Excel Power Query function, I came to SQL understanding almost all the concepts already and I only needed to learn the syntax. I would say I could answer about half these questions and I'm only three weeks into SQL but a year and a half into Power Query. This was a really helpful video! I'll check out the blog. 🎉🎉🎉

[@explodev2550]

Hello are you working now?

[@devendraraghuwanshi3136]

From Madhya Pradesh, !!May the grace of Mahakal always be upon you!! TFQ Thanking for helping people to get in IT at no cost, really your teaching style and content is priceless ,, Thank you for offering Data analyst skills FREE

[@techTFQ]

Thank you for the blessings buddy 🙏🏼🙏🏼 Happy to know you liked it

[@RamzanAnsari-eo4hs]

A few months ago I had decided to learn sql to prepared for the interview and to unskilled myself after searching through out the day to confirm who KZbinr video best of me and unfortunately came across to taufiq sir videos and it's one of my beat decision to choose your KZbin channel. Thank you taufiq sir❤

[@dany21tr]

"good question you can check the answer in my blog, next question oh you can definitely check the answer in my blog"

[@surazsunny4203]

its so irritating

[@enshk79]

You're my SQL HERO, Taufiq!! Thank you for everything you do. You've helped my understanding IMMENSELY. So grateful for you!

[@ft_peakhd2921]

Hi Taufiq, Small change for question 11, In mYSQL you could even write it as Select substring_index(full name,' ',1) from table_name this will give you the required o/p. This query makes it simple to understand and gives the result much faster .

[@sabhrang4013]

I am very new to SQL. I have been studying for less than two months.Your videos are so easy to follow. Good command on English language. Keep up the good work. I will be watching more often. Thank you.

[@techTFQ]

Awesome Sabhrang and thank you for liking my contents ☺️ Happy to read this comment

[@AfsarJan]

every answer to his question is his blog guys. in the video, his answer for every question is check my blog, so don't waste your time and skip this video.

[@p_anjali_codes]

Thank you for coming up with this video. It helped me to get a glance at what to expect in interviews.

[@SagarKumar-db2xy]

This was definitely Helpful. As a fresher we r often confused on what and how much to study.. Please make few videos on Stored Procedures and Functions as well. Thank you for everything you are doing.

[@techTFQ]

Your welcome bro.. glad this helps

[@akshaykumarsingh9770]

You are doing great job Thowfiq. And I mean it. I'll tell all of my students to follow you. I have been following you for a while and I got you and your work. Very strong, real and tough content you provide. That's awesome.

[@techTFQ]

Thank you Akshay for such kind words 🙏🏼 Truly appreciate the support ☺️

[@HenrryWith2Rs]

I’m going to your blog and I respect your hustle, but ITS HILARIOUS that most of your answers on the video are “yeah just check my blog”

[@santoshsable1]

I am a beginner in SQL and want to know if you will be creating any learning videos for absolute beginners. I like the way you teach. Looking forward for videos on SQL basics.

[@techTFQ]

Thank you for liking my contents and yes I plan to make a complete SQL tutorial series covering all SQL concepts soon

[@bhaskarkotini4894]

@@techTFQ even I am waiting for your SQL complete video series

[@techTFQ]

Thank you 🙏🏼

[@yogeshmishra261]

As an experienced person, I get asked on below questions - 1. materialized view 2. difference between temp table/ table variable/ CTE 3. Union vs Union all 4. table statistics 5. execution plan 6. isnull() vs coalesce() 7. table partitioning

[@nirmala3847]

How many years of experience you have sir

[@BipinKumar-ou7tj]

Q11. We can solve this problem in Postgres DB by using Split_Part function. Select split_part(full_name,' ',1) Note: use 1 for first part of string separated by a character, in this case we have space ' '. 2 will give the 2nd part of string and so on...

[@sanketshambharkar3687]

IN THE 11 th Quation we will use a concate function not a substring or instring bcoz substring-used to return a requierd string like ('varun',2,4) output-arun instring- return a location of a string like ('varun','u') output-4

[@Sakshiraghuvanshi0323]

That’s a gem! I thank you on behalf of all the people who watched this video but didn’t give a thumbs up. 👏🏻

[@techTFQ]

Thank you ☺️

[@pio024]

thanks very much for creating this video and even someone like myself with 20 years of Oracle Experience found it very useful and was asked so many of these questions which have been mentioned in this video when I was attending interviews in the UK, so would recommend to watch it before your interview!

[@techTFQ]

I am so glad that even an experience professional like you too found this helpful 🙏🏼🙏🏼 All the best with your interview 👍

[@johnetim5274]

Nice... Someone with minimal IQ like me is really loving the comments.. I crave to understand sql at 56years old despite some of the complexities in learning code et al. I CAN DO IT.

[@sourabhbhandary1181]

A quick analysis of the video. Actually, I was looking for an explanation of the answers or a brief answer to the questions, but you just advertised your blog in this video. The questions are authentic and reasonable but what I was looking for was not to visit any blog, that's why I searched on youtube.

[@balajivijaykumargoli3114]

Really hats off to you Sir. Very patiently and explained with detailed information .

[@techTFQ]

Thank you :)

[@arulvishwakarma007]

I am a DA and i can say that all these questions are very common and are asked alot ! whereas these questions are only limited till interviews and are of no use in day to day activities... therefore whatever is told in the video is more than enough to crack SQL questions and answers. But I highly suggest DATA LEMUR to practice your SQL coding skills

[@nelsin11]

SQL in different sql versions is something I appreciate on your blog. 👍

[@krishnabathula4104]

You are helping to all SQL folks alot by making these kind videos as well as your blog which are having great contents. I can not thank you enough. 😊🙏🏾

[@techTFQ]

Thank you Krishna :) I am glad this helped 🙏

[@krishnabathula4104]

@@techTFQ pleasure is mine sir.

[@laurak5196]

I just came here to say look at you fly with 166K!!! And you deserve it, Thoufiq, content always right on point. Thank you 🙏🏻

[@techTFQ]

Thanks Laura 🙏🏼 As always very kind of you ☺️

[@debapriyabehera7146]

I am Subscriber when watching your first video.... It's just waooo concept clear.... And feeling myself self confidence in SQL ....thanks... After watching every video... And saying it's truly after learning SQL from you .... interest in learning and making career in data field more only on in SQL.... Thanks a lot.🎉

[@techTFQ]

You're welcome ☺️ All the best

[@ajithreddy]

Q.11)> select substring(full_name,1,instr(full_name,' ')) as first_name from dual; select left(full_name,instr(full_name,' ')) as first_name from dual;

[@jaggu_90]

your voice is so soft and clear....that is verry impressive and easy to understand......this vedio is helpfull

[@chithrac9600]

Thank you. Those are very good questions and you have explained them very well. Great tutorials. Definitely would be helpful for everyone.

[@techTFQ]

Glad you liked it

[@LAKSHITBHATNAGAR]

Hi Taufiq , Thank you for all the videos on SQL and Python .YT also helped me found this gem channel and now I am preparing for my upcoming interview for an IT senior analyst from your channel .My SQL fundamental has improved in a week .I hope to learn from channel through my Data engineering and Business analytics journey .Thanks again for the awesome content .Appreciate your great work to the people .

[@Sesquipedaliofobia]

Hi, how did it go?

[@jsmithers.]

​@@SesquipedaliofobiaHe didn't get it..

[@spartan2906]

I'm following your videos for all my sql concepts. And guess what I'm struggling with JOINS bcoz you didn't cover it yet. That's a level of dependency I have on you...😂😂 Plz upload JOINS !! In the same way you explain with help of complex questions (that's matching with my way of learning ). Many many thanks 👏

[@techTFQ]

Haha this is a big dependency bro 😬😃 But I’ll definitely consider making the joins video soon ..

[@simranbanwait]

taufiq bhai thankyou so much

[@techTFQ]

Your welcome buddy

[@girijashamak9142]

Happy to see the growth of your channel young man. Very much deserved . Appreciate your time and efforts . God bless 🙏

[@techTFQ]

Thank you so much Girija :) Truly appreciate the blessings 🙏

[@laurak5196]

Another great video and so much preparation and work went into this. This is going to help so many people. I’ve watched a lot of videos about SQL interviews but this one is the most detailed and I love the supplementary information on your blog too. As a beginner in SQL, there are definitely concepts here that are brand new to me. Because this video is good for all skill levels, I would find it helpful to have a note on the blog as to which concepts are important for beginners to know vs intermediate vs advanced. You explained it well here but I think it would be good to see it there as well. Thank you again for all of your help, Thoufiq. One thing I can guarantee is that anyone who interviews me will hear about you because I have learned so much from you! 🙏🏻😀

[@techTFQ]

Thank you Laura 🙏🏼 You are the best .. That’s a good suggestion.. I’ll try to edit the blog once I get some free time this week.. Nothing makes me more happier than to know that these videos have helped you and so many others to learn SQL 🙏🏼🙏🏼

[@laurak5196]

@@techTFQ I am sure you are so busy and I hate to ask for anything, to be honest, because you’ve shared so much, but I think if the goal is to help as many people as fast as possible that from an efficiency standpoint, it’d be good to either have them categorized for difficulty level or have a note at the beginning as to which ones beginners etc should focus on. Again, I want to thank you for your time and for doing such detailed and thorough work.

[@techTFQ]

No problem Laura .. I am always open to suggestions so I can improve my contents .. It’s a valid point you make so will definitely consider it..

[@laurak5196]

@@techTFQ I’m really glad you made this video because without it, I may not have prepared for some concepts in here that I had never heard of. I haven’t even had a chance to go review your blog post yet, but you can be sure I will be doing that as well. Thanks again for your help 🙏🏻

[@techTFQ]

Glad to hear this Laura.. I wish this helps you to clear any SQL interview in the future

[@scarefacearinze5981]

I discovered your channel today. excellent contents. Straight to the point with clear examples

[@ishagupta972]

best content on internet. glad to find you

[@techTFQ]

Thank you Isha :) Glad you liked it.

[@healthboostup44]

Reallly so helpful and so clear

[@techTFQ]

Glad it was helpful!

[@dhirajdahale4687]

Very helpful.. 👍 Please make a video for those who are switching there career in database Because it's difficult to get a job as a fresher..

[@techTFQ]

Thank you Dhiraj 🙏🏼 Will consider the suggestion for a future video

[@gparvez6695]

This video is very helpful and thank you for the blog aswell.

[@techTFQ]

Glad it was helpful!

[@maruthimadhu2250]

Could you please share the blog link

[@karlajusten]

I recently learn that 'Ess-cue-ell' is deemed the correct pronunciation of SQL. 😅 So far I would pronounce the letters 'S-Q-L". During an interview I said I didn't know "esscuell". But after some discussion I learned it was SQL. Almost lost a opportunity there. 🤭

[@rameshchavda4117]

what a perfect explanation alongwith cool mind , many things learned from u like sql

[@techTFQ]

Glad to hear that! Thank you Ramesh :)

[@9242224526]

Thanks for your time and Knowledge sharing.Your videos are very much helpful for serious learners.

[@techTFQ]

glad this helped

[@saudahmed9962]

Answer of all questions "i explained in my blog"💁, although blog is written very good you should explain main points instead of just pointing towards blog. Thanks for question bank.

[@vijayalaxmi648]

Hello, I am also preparing for sql beginners level interview. I hope this videos make me successful in my interview ✌

[@robalarcon]

Thank you for the video and the blog post, I did not remember that Triggers are a thing I haven't used one in a decade 😅

[@Freakouts_and_found_Insane]

Best video I have ever seen on SQL ....🙏👌

[@techTFQ]

Thank you Rushikesh 🙏🏼 Glad you liked it ..

[@bumblebee2012able]

Thank you, your video helped me a lot, If yes, can you please make a video on how to improve query performance, again thanks for all of your time so far.

[@techTFQ]

glad it helped and noted on the request

[@1112electronics]

Thanks for the awesome video on SQL .. please keep it up...the way you explain is really great... thank you so much Bhai...

[@techTFQ]

glad you liked it

[@giovannymartinez1147]

This video is gold, thanks bro!

[@techTFQ]

Glad you liked it buddy

[@lalithasrithabandaru2642]

Followed most of your videos. Amazing content. I would request you to make videos on Packages, Functions, Stored Procedures, Triggers

[@techTFQ]

Thank you so much 🙏🏼 Sure will do

[@satyaece2007]

@@techTFQ yeah I second that, can you please make videos on PLSQL concepts, it would really help lots of folks considering the way you explain!!

[@techTFQ]

Noted Satya , will plan it for the future

[@satyaece2007]

@@techTFQ Thank you !! If I'm not asking for too much, Can also please make one on query plan ?

[@techTFQ]

Performance tuning is something I will do in the future

[@anaskhan4841]

What a great resource your channel is! MashaAllah love your content and your course on lighthouse.

[@techTFQ]

Thank you Anas :)

[@-VAISHNAVID]

Thanks for your valuable blog.. It is so benefit for students like us to clear our technical interview.

[@harshshah9006]

was able to answer all except 4-5 . Thnx for this.

[@qwesence1]

Thank you! This is a big help. Thanks for breaking it down

[@martinfernandezcean]

Your content is great and very very helpful. Thanks from Paraguay

[@minalwaman8629]

Thankyou very much.. its really helpful ..

[@techTFQ]

Glad you liked it

[@MyWorld-tz1pl]

Hi sir, Great video. Please make video on Query execution plan and Optimization.

[@techTFQ]

Thank you and will consider making those videos in the future 🙏🏼

[@mathieudager4234]

Once again, great content here. Would you consider turning these questions into a downloadable Pdf ? That would really be much appreciated and helpful. Thanks in advance

[@techTFQ]

Hi Mathieu, I’ve posted all these questions on my blog but making them as pdf is not something I am considering as of now..

[@thomaspfanstiehl6156]

Great idea I was thinking of the same thing !

[@techTFQ]

May be will consider it for the future contents

[@hopecelebre3083]

Spot on! You’re videos are very reliable! ❤❤

[@sribastavrajguru304]

Truely amazin gcontent. No waste of time, right to the point, precise, nd most importantly valuable content. Waiting for a detailed practical session on different types of joine(intermediate and advanced).Thanks

[@techTFQ]

Thank you Sribastav 🙏🏼 Glad to know you liked it

[@dattatrayarathi1014]

Thank you for all details information 🙏🙏

[@techTFQ]

Your welcome 🙏🏼

[@keerthivardhan2310]

Haii Thofiqq Great Explaination about SQL really crystal Clear and Awesome keep Going...

[@techTFQ]

Thank you Keerthi

[@naodtewelde8607]

All your courses are clear, easy to understand and very interactive. thank you for your time and effort.

[@techTFQ]

Thank you Naod 🙏🏼 So glad to read this ..☺️

[@beyond_success]

Your tutorials helping a lot, please explain pivot in mysql

[@techTFQ]

MySQL does not have PIVOT but we can do same thing in mysql using CASE statement. I have explained it in my leetcode video

[@pujashree2402]

Great video, before interview I watched and more or less I got this questions. Tysm 😃

[@selectstation6827]

Great deal brother. I appreciate the knowledge. You the man.

[@gauravmathur56]

It helped me a lot in my interview journey .

[@Kushbukushbu770]

Thank you so much TFQ ..ur videos are more useful ❤im following ur videos and learning SQL

[@techTFQ]

Great it could help

[@Ragima001]

It was good that you reminded me of these. Thanks a lot

[@issakhanhemat8882]

So happy to have you kind of teacher ❤️❤️❤️❤️ thanks Afghanistan 🇦🇫🇦🇫🇦🇫

[@shawnmendoza3321]

Loved this ❤ Just watched.. Thanks

[@techTFQ]

Thank you Shawn 🙏🏼

[@srt5806]

Great article & Video on SQL Interview Questions! Please make videos on Sql query performance tuning.

[@techTFQ]

Thanks bro.. will make video on performance tuning in the near future

[@samarthkulkarni5069]

Hello Toufiq thanks for this Video you are really good Educator ...few Questions 1. I am using MS SQL > What is Commit function ? As you mention in Delete VS Truncate difference statement.(Reference Question 2)

[@rajn2155]

Commit function is used to save the changes in database. So if we deleted some records using delete command(dml) ,we can undo it. If we deleted records using truncate command(ddl) and commit then further we can't able to undo it as truncate will remove the space occupied by the the fields.

[@samarthkulkarni5069]

@@rajn2155 Sorry for Followup question how to Undo it if already deleted ?

[@dineshganyarpawar5441]

@@rajn2155 "If we deleted records using truncate command(ddl) and commit" - commit is not require for truncate command. it is auto commit. rest is correct. Truncate will reset the High water mark.

[@dineshganyarpawar5441]

@@samarthkulkarni5069 use rollback; to Undo

[@rajn2155]

@@samarthkulkarni5069 using rollback command

[@nishantchauhan6164]

Solution to question 11 can also be done using split method, I remember I used it earlier on SQL server.

[@abhisheksinghrajput2611]

It is very healpful for us.

[@techTFQ]

Glad to hear this bro ..

[@naveensriram9866]

@@techTFQ how to take course from you 😊

[@deepakgauba3592]

Sir for Q.11 you can also simply do it by writing SUBSTRING_INDEX(FULL_NAME, " ", -1)

[@rick2591]

Great video, always a good idea to brush up on whatever SQL instance the company will be using... In some db systems procedures that work far differently than they work for SQL Server, MySQL, Oracle. Others, like Postgress allow embedding an update in a cte... Keeping them all separate is a challenge.

[@techTFQ]

That’s right .. some rdbms have certain enhancements which are very useful like the one you mentioned..

[@mohammedshahil4898]

Indeed the best video out there regarding SQL interview questions👌🏻👏🏻 It was truly helpful. Thanks a lot brother🙏🏻 As you have mentioned, Looking forward for the detailed JOINS video🙌🏻

[@techTFQ]

Your welcome hero ❤️❤️ Will do JOINS video soon

[@adarshsharma356]

Thank you so much sir ❤️☺️ really helpful .. i appreciate your hard work .. u did a great job .. your blog is just awesome 👍😎😎❤️

[@techTFQ]

Thank you Adarsh. glad you liked it :)

[@waelbreich7644]

Thanks Thoufiq. I've been following you for a while and this is my favorite SQL channel. Regarding question 11, would a Like operator with the % wildcard in MySQL work: select * from table_name where full_name like "Elon%"

[@techTFQ]

Thanks Wael for liking my contents 🙏🏼 Appreciate your kind feedback. As for question 11, you need to just fetch the first name from full name field so using % u cannot do it. U can use % (as u mentioned above) to filter records to fetch all records that start with Elon

[@waelbreich7644]

@@techTFQ Makes sense. Thanks for replying and for the amazing content man!

[@techTFQ]

Your welcome buddy

[@splashoui3760]

@@techTFQ Because you are being exptected to filter the first name for all the rows in a specific column. By using "Elon%" you can not filter Jeff Bezos.

[@septimus__Prime]

Thank you so much. I have an interview tomorrow

[@nani363542]

If KZbin allows me to subscribe again and again.I will subscribe more than 100 times. You are amazing. Thank you so much.

[@techTFQ]

Haha thank you so much Behailu 😃🙏🏼

[@johnpg3055]

Great content Thoufiq.. Your videos are really helpful. Waiting for your complete SQL tutorial series.. Functions, Stored Procedures, Triggers, etc. Thanks a lot.

[@techTFQ]

Thank you John 🙏🏼 Will make those soon ..

[@tonyjinca]

Thank you Sir, I love your helpful videos!

[@techTFQ]

Your welcome bro Glad you like them

[@merlinevinter3766]

Thanks a lot for your Videos on SQL!!!

[@dimasdebyolyy7336]

It is soooo useful video. Thank you a lot

[@techTFQ]

glad you liked it

[@NeverStopLearning56]

Very informative , Thank you brother

[@techTFQ]

Your welcome bro 🙏🏼

[@chrisumali9841]

Thanks for the demo and info, have a great day

[@buvaneshb423]

thank you for the wonderful information

[@techTFQ]

Your welcome 🙏🏼

[@TrendingVideo1490]

Thanks Taufiq, you are good at explaining the concept

[@pveeranjireddy8959]

Thank you for Sql video. Could you make videos on nested joins .In real time organizations are using big joins .It challenging to understand while got stuck or error.

[@techTFQ]

Your welcome 🙏🏼 Yes will cover joins soon

[@sonalilagnajita8740]

Hey Thoufiq, your videos on SQL are really great. They are easy to understand and fun to practice. Your videos helped in shaping my basics. Thanks a ton. Lucky that i found your channel. Got a request. Please make a video on join & Regular Expressions.

[@techTFQ]

Thank you Sonali 🙏🏼 Glad to know you contents have helped you ☺️ Will make video on Joins soon and regular expression may be a little later

[@adityagupta9257]

please make series on these topics it will be very helpful

[@techTFQ]

Will cover it as part my sql tutorial series soon

[@deepthirayala6055]

Thank you so much, sir your teaching was superb 🔥🔥🔥🔥🔥🔥

[@manuvats523]

Great content mate. Can you please provide one video on how to learn writing stored procedure. Its a mental block for me. A tutorial will be great !

[@techTFQ]

Thanks Manu , Sure will cover procedure soon

[@anuragbawankar685]

Thanks a lot Sir !!!

[@techTFQ]

Most welcome!

[@mtariqmail]

Hi Taufiq, Great Video but I would suggest including all the details of your blog in this video instead of referring blog to read more details. It's just a suggestion but a blog is also great. Thanks again.

[@aadarshchaudhari3957]

Thank you Bro your videos is very helpful.