Solving SQL Interview Queries | Tricky SQL Interview Queries

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2 жыл бұрын

In this video, I will explain and solve 3 tricky SQL Interview Queries. These are the SQL Queries which can be expected during SQL Interviews for both beginners and experience level interviews.
Many times, SQL Queries given during SQL Interviews are more tricky than complex. The solution to the SQL question may be simple but understanding the question and dataset and analyzing the data will play the most important role when solving such SQL queries. Hence mentioning the tricky SQL queries which you may expect during SQL interviews.
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Thoufiq

Пікірлер: 469

@ManuelrPM24 Жыл бұрын

For the second one in oracle this query also does the trick in one single query SELECT NVL(A.ID,B.ID) AS ID, CASE WHEN B.NAME IS NULL THEN 'New in Source' WHEN A.NAME IS NULL THEN 'New in Target' ELSE 'Mismatch' END as Comment1 FROM source A FULL JOIN target B ON A.ID = B.ID WHERE NVL(A.NAME,'$') NVL(B.NAME,'$'); I used full join and excluded the names that matched then is just added the Case. Great Video!

@lakshmipriya8416 Жыл бұрын

I am really thankful to you .. few months ago I was not so confident on myself to give interviews.. after started learning from your videos given around 4-5 interviews confidently. Thank you😊..

@vinodhkumar4660 Жыл бұрын

Miss likshma how to apply interview

@vinodhkumar4660 Жыл бұрын

Plz tellme

@happyji2624 Жыл бұрын

I wanna ask too

@vlog.444 4 ай бұрын

அருமையான எஸ் பி எல் வினாவல் அருமையான எஸ் பி எல் லாங்குவேஜ் சொல்லி கொடுத்ததற்கு நன்றி

@darshpancholi4919 2 жыл бұрын

Please add this video to the SQL playlist! Started watching the joins video and I have never seen a better explanation before. Love the content!

@madhusudhanreddyt2838 2 жыл бұрын

The way you explained and the pain you have taken to make such wonderful videos is way beyond saying thanks...you are a rockstar man....keep posting such kind of tricky queries...will help someone get a job...all the best bro...

@techTFQ 2 жыл бұрын

Thanks a lot bro

@HotThupka 2 жыл бұрын

He is a savior. I am lucky that I came across his videos. Such a lucid explanation. Thank You. Please upload more of SQL Queries needed for Data Science Folks !!

@techTFQ 2 жыл бұрын

Glad you liked my contents :) thank you

@HotThupka 2 жыл бұрын

@@techTFQ My Pleasure, its for my benefit

@rhys4473 Ай бұрын

That last example was lit! I was having difficulty understanding recursive CTEs before, but now I clearly get it.

@srushtiOm 2 ай бұрын

I could come up with this - select comment from (select * from comments_and_translations where translation is null) x union select translation from (select * from comments_and_translations where translation is not null) x

@klokeswarreddy3205 2 жыл бұрын

Sir, can you explain about what exactly a sql/ plsql developer do in software industry and what are the career growth options in future for sql developers in IT industry. Is it better to go through in that domain?

@siddheshaddarkar4074 3 ай бұрын

Logic is correct... In second query you have used union operators and same table is scanned 3 times which may not be suitable for big tables... We can use cte for the same

@karthikvenkataram4790 Жыл бұрын

Thanks a lot TFQ. Your videos is not just a video it is a service for many techs like me. Beautiful explanation that too for tricky questions. More than that the SQL commands to execute and practice in our IDE's that you share get me more to my fullest satisfaction. A special thanks for that too buddy. Please keep up the good work.

@bedaprakash9609 11 ай бұрын

I just got to know He is from Malesiya , such really amazing contents not finding anywhere in youtube , please keep posting more videos like this 🙏🏻🙏🏻, really feeling like big brother is helping to understand such complex things in a simpler way 😇, Love from India 🥰

@westgot2 Жыл бұрын

I wouldn't ever hire the one who solves the second task like you did. This is the clear task for the FULL JOIN

@harsohrabsingh8020 Жыл бұрын

The best channel to learn sql topics as well as solve questions.

@akhilreddy5208 2 жыл бұрын

You are really explaining the complex queries which will be very helpful for professionals as well

@techTFQ 2 жыл бұрын

Glad you liked it

@ektashah07 11 ай бұрын

query 2: without joins select id , case when id = 3 then 'new in source' else 'mismatch' end as output from source where id in(3,4) union select id ,'new in target' as output from target where id in (5) OR select id , decode (id ,3,'new in source',4,'mismatch') as output from source where id in(3,4) union select id ,'new in target' as output from target where id in (5);

@ganeshv791 2 жыл бұрын

Hi, Your videos are very unique and easy to learn Can you please make videos related to Grouping sets, Rollup, Within group. And also please make related to dynamic sql Thanks for your time.

@techTFQ 2 жыл бұрын

Thank you bro and noted on the request

@Hsalz 5 ай бұрын

You are simply amazing, Thoufiq! I took your SQL Bootcamp last year and often come back to your content for additional practice and learning. Stay blessed!

@VibeQueen24 2 ай бұрын

Thank you sir, for making such informative videos. it's really helping me practice for my upcoming interviews. One request is to please make videos on puzzles and guesstimates for full practice for the role of data analyst.

@shailajakesani8048 2 жыл бұрын

Hi, i have attended interview recently and they asked question about which command is used to find error? Could you please help this? Thanks in advance.

@unawarenoob2968 Жыл бұрын

Write any wrong query and u will get the error!

@santoshk4789 Жыл бұрын

@@unawarenoob2968 😂

@aniketdhale7510 Жыл бұрын

@unawarenoob 🙏🏻🙏🏻🙏🏻🤣🤣🤣

@immagod5285 Жыл бұрын

Where r u now? Placed? If yes... where

@Kamina_Insaan1 10 ай бұрын

Begin catch

@yrrep27 Жыл бұрын

Alternate solution for problem 2 in postgres-- It's essentially 3 steps: 1 Use a FULL OUTER JOIN on id to combine all the records 2. Use WHERE to pick out the rows where a) Source has a null id, b) Target has a null id, or c) Source name differs from Target name. 3. Use two CASE statements in SELECT to pick out the non null data and hard code in our comments.

@007SAMRATROY Жыл бұрын

The conditions can directly be used in the case statement I think.

@PeachesO-NE 11 ай бұрын

Then Order By DESC COMMENTS

@ashutoshkumar-gv7wu 2 жыл бұрын

Kindly come up with real life Day to day activity a SQL Developer or a data analyst does in the industry or the company. Like please explain when we join any company how are these Query useful there with some kind of live examples. For instance how a data analyst uses SQL in his day to day work at the office. Also please continue providing such videos and please come up with full tutorial videos in a sincere format like a course

@techTFQ 2 жыл бұрын

Noted on the request bro, let me think about it

@archana-sv1hh 6 ай бұрын

Hey Taufiq, Could you please make a video on indexing .You explain very well. Want to understand SQL indexing thoroughly but couldn't find any video on your channel. If you already have made video on it, could you please share the link here?

@shivashankargopal1678 2 жыл бұрын

Thanks a lot TFQ for giving such wonderful explanation for all these questions. I started watching your YT channel a month back your teaching style and your logical explanation for each concepts MINDBLOWING. Thank you again for sharing your knowledge.

@techTFQ 2 жыл бұрын

Thank you for the kind words bro 🙏🏼🙏🏼

@sumitbarde3677 2 жыл бұрын

hi taufiq, the approach for 3rd problem was out of the world. thanks for such a mind-blowing approach.

@techTFQ 2 жыл бұрын

Thank you Sumit :)

@Kabboch 2 жыл бұрын

For question 1 I would use Select isnull(translation, comment) from table

@jameses4413 2 жыл бұрын

Me too, much easier…

@prabhatgupta6415 Жыл бұрын

@@jameses4413 yes

@venkateswararaodevisetti8684 Жыл бұрын

Nice question and answers However the third question can be solved without rownumber() as the < can be directly applied on team code

@NageshwariShankarappa 26 күн бұрын

good explanation with all examples. Thank you

@sparshmittal705 2 жыл бұрын

Hi sir, we can write it like this select id , case when id=3 then "New in source" When id =4 then "New in target" When id =5 then "mismatch" End as comment From source Full outer join target Where source.nametarget.name

@techTFQ 2 жыл бұрын

Yes right.. I have provided solution using full outer join in my blog

@cococnk388 10 ай бұрын

Thanks TFQ the last question was everything, I was blocked on how to remove mirror effect records from my query.

@SunithaRamalingam 25 күн бұрын

very very helpfull, thank you. will be usefull if more such videos are brought out

@krishpoptani7862 Ай бұрын

The video is quite informative, and way of teaching is great.

@tarunsaha439 2 жыл бұрын

Great explanation. Looks like for the third query you had already solved the second part first using not equal on team names.

@techTFQ 2 жыл бұрын

I did but I wanted to provide a more meaningful and easier to understand solution at the end hence used row number concept

@zishan53 2 жыл бұрын

Nice one I feel very relax to solve them Thanku very much

@sathishkumar-yd3pk 2 жыл бұрын

Very smart query. Thanks for sharing this query

@techTFQ 2 жыл бұрын

Your welcome buddy

@debasismohanty1311 6 ай бұрын

Really you are born to teach .just loved your way of explaining Thank you so much

@Madanmohan-ns3fi Жыл бұрын

For the 3rd question 2nd problem, we can also write simply by using cross-join. Learned from your videos :) select team.team_name as team, opponent.team_name as opponent from teams team cross join teams opponent where team.team_name opponent.team_name Regards, Madan

@arturabizgeldin9890 8 ай бұрын

and since we are able to compare string values we can solve the 1st problem with just adding condition "AND team.team_name > opponent.team_name". it is true only for pairs of two different values.

@deepaksoni2667 2 жыл бұрын

your videos helps me a lot to solve complex queries...

@techTFQ 2 жыл бұрын

I am glad to hear that buddy

@odaya9946 2 жыл бұрын

Your exemples with the excel really helped understand the logics, thanks!

@techTFQ 2 жыл бұрын

Glad you liked it

@ctnrandhawa7019 Жыл бұрын

great your way of explaining problem and solving them adds fun for them also who thinks sql very tough .great job sir.

@suryakantchavan4887 2 жыл бұрын

Words are not enough to say thank you , love this bro , GBU

@techTFQ 2 жыл бұрын

Glad you liked it buddy :)

@maidelfigueredo4596 Жыл бұрын

Thanks for your videos, very helpful for me when I started to find a job. Thanks a lot

@srinubathina7191 Жыл бұрын

the way you explained is next level Sir Thank You so much

@amit.pawase007 2 жыл бұрын

Thank you so much for the thoughtful explanation. 😊 One thing came into mind, 2nd query with union of 3, instead, can we use full join with case statement to print the desire output?

@essalinas2944 2 жыл бұрын

He said yes - see his blog

@infamismworldwild6248 2 ай бұрын

Thank you this was powerful and expanded my understanding on the application of SQL

@2011var Жыл бұрын

God bless you. Taking your precious time and helping others.

@murtazajabalpurwala8124 2 жыл бұрын

thank you so much. superb video

@techTFQ 2 жыл бұрын

Glad you liked it

@nirmaldas4749 2 жыл бұрын

excellent work sir !! please come with more practical example like this ,,

@techTFQ 2 жыл бұрын

Thank you Das and will do

@rakeshkumarrout2629 2 жыл бұрын

Guyz watch everyday Data science channel where he already solved so many leetcode interview questions.. Probable qsn for interview.. Do watch tfq.. Of you stuck somewhere get help there.

@techTFQ 2 жыл бұрын

Thank you Rakesh :)

@ayazahamed8254 Ай бұрын

Very Well Explained.

@waghdipak2358 2 жыл бұрын

really, very appreciative video and the channel itself fro learning sql. Thanks a lot sir for providing this.

@techTFQ 2 жыл бұрын

Thanks you Wagh :)

@pratyakshaparashar5306 2 жыл бұрын

Thanks. Thanks a lot. Your concepts are easily understandable.

@techTFQ 2 жыл бұрын

Glad to hear that bro

@darshanwala5561 Жыл бұрын

very helpful all the sql queries examples thanks brother please share more the complex sql queries real life examples

@amanadhikary8030 2 жыл бұрын

it was amazing learning. Please make something on normalization if possible

@techTFQ 2 жыл бұрын

Thank you and will consider your request

@manojkumar-kq1nc 2 жыл бұрын

It will be very helpful

@misterihorror1993 Жыл бұрын

there's many way to do the second query.. it's pretty easy.. the third one now that is challenging!

@gyanprakashmishra9132 Жыл бұрын

you are best educator ever for sql 🙏

@ZVideo 2 жыл бұрын

Hi Tawfiq, Thank you so much for your amazing efforts, can't we use full outer join and Case When with the second Query instead of using 3 queries and union

@techTFQ 2 жыл бұрын

Your welcome bro and yes you can use full outer Join too.. I have mentioned it in my blog with the full outer join solution

@manoganesan7618 2 жыл бұрын

I Believe, We can use EXCEPT operator which will print the unmatched data from required tables.

@satyabadiraut1191 2 жыл бұрын

Excellent explanation...thank u so much for such kind of sessions.

@techTFQ 2 жыл бұрын

Most welcome bro!

@ankitapriya13 2 жыл бұрын

Sahi video, sahi samay par!

@techTFQ 2 жыл бұрын

Hope this helps 👍

@rajasekharareddyb668 Жыл бұрын

Really good explanation.. easy to understand even the problem is very complex.. thank you so much for your time

@zacharyrohrback 4 ай бұрын

Thank tou for serving us the knowledge we need!

@rameshchavda4117 2 жыл бұрын

dear ftq salute on your explanation on sql subject

@techTFQ 2 жыл бұрын

Thank you buddy

@ruheequreshi9741 Жыл бұрын

you have excellent way of explaining the query and how system works.. really great videos.. good work

@abhishekgowda1776 2 жыл бұрын

Thank you for sharing another great video.. Please make video on data import, export and back-up. Thanks for your time..

@techTFQ 2 жыл бұрын

Thank you Abhishek and sure will do :)

@user-lk7zt8cp2g 2 жыл бұрын

How to split a string into 2 strings and make first and second as capital letter. Example goodmorning(no space) -Good Morning

@user-om7le1cs5i Жыл бұрын

hello all , here is my query with easy understanding for the last IPL match query . For each team play with every other team twice , here we can use cross join ... select IPL.team_name , O.team_name from IPL ,IPL as O Where IPL . teamcode O. teamcode I never imagined that i can also write a query with understanding SQL thank you techTFQ

@sulaimansheikh6050 2 жыл бұрын

Hello, You are doing a great job with a good explanation. please make a detailed video on Database Performance Tuning

@techTFQ 2 жыл бұрын

Thank you Sulaiman and sure will do

@jitendrashelar4123 Жыл бұрын

Excellent! Thank you very much. Such a hard concept to understand, you made so easy sir.

@guzmanerpr 8 ай бұрын

Thank you for taking your time to explain this.

@techTFQ 8 ай бұрын

Glad you liked

@ratneshraj4653 2 жыл бұрын

Very nice, Please make videos on Stored procedure and User defined functions wrt its usage in job.🙏

@techTFQ 2 жыл бұрын

Thank you and sure will do

@nishapandit5131 10 ай бұрын

Wonderful expiations, especially the last question has a newer nuance..

@bharatk212 2 жыл бұрын

Just Awesome Brother ! SQL is an ocean and you're helping others to voyage !!

@techTFQ 2 жыл бұрын

Thank you buddy

@ashutoshbafna6617 2 жыл бұрын

Very useful . I was under impression to join table only = can be used , you shown less than symbol also works . First time seen use of coalesce function . Can you list down such rarely used but imp. Functions and what are names in different RDBM , is same available in MySQL ? I really Appreciate your efforts and excellent work. looking forward to more such videos.

@techTFQ 2 жыл бұрын

Thank you bro , glad this helped .. And noted on the request, will consider it

@utubemovies1 Жыл бұрын

The 3rd question is very good.

@arielfishel4662 2 жыл бұрын

Great video, thank you

@techTFQ 2 жыл бұрын

Glad you liked it!

@timopheim5479 Жыл бұрын

Solving question 2 you should perform a full outer join, select rows that have null values in either source or target name or names that mismatch. and use an ifelse function to name the occurences in the variable Comment. Here is the code (with data) using data.table package in R: library(data.table) x1=c(1,2,3,4) x2=c("a","b","c","d") y1=c(1,2,4,5) y2=c("a","b","x","f") X=data.table(id=x1,name=x2) Y=data.table(id=y1,name=y2) merge(X,Y,by="id",all=TRUE)[name.x!=name.y | is.na(name.x) | is.na(name.y),.(id=id,Comment=ifelse(is.na(name.y), "New in Source (X)", ifelse(is.na(name.x),"New in Targe (Y)","Mismatch")))]

@souvikmaitra6653 Жыл бұрын

We want more n more videos like this... excellent work...keep it up ...

@anirbansarkar6306 2 жыл бұрын

This is really wonderful video. Thank you so much. Please do come up with such wonderful contents.

@techTFQ 2 жыл бұрын

Thank you bro

@traumegaz 10 ай бұрын

thanks teacher, im learning alot your a great teacher

@aryanaboyaryayeenezhad7295 2 жыл бұрын

Good job Towfiq Jan!

@techTFQ 2 жыл бұрын

Glad you liked it bro

@solahope6474 Жыл бұрын

Thank you very much , very helpful

@bmanikanndan 2 жыл бұрын

Awesome Explanation on Third Query... Thank You so much.

@profebarry 2 жыл бұрын

Thanks for your important videos. Do you have a video showing the way to proceed with mySQL SELECT queries binding data from variables?

@techTFQ 2 жыл бұрын

Your welcome but until now I haven’t made a video about it

@bhanuchandarpr1122 2 жыл бұрын

Ur way of explanation is super, Keep go like this sir

@priyaranjan9358 2 жыл бұрын

It's really helpfull. Thank you...

@techTFQ 2 жыл бұрын

Thank you 🙏🏼

@technicalmaster4066 2 жыл бұрын

Just trying to understand in second example you have used three joins instead of that can’t we use full outer join and compare source and target using case to get comment value?

@techTFQ 2 жыл бұрын

Yes you can solve it using full join too .. Just that not every rdbms supports full join so I used this solution but I’ll add solution using full join too in my blog.. Thanks for suggesting

@maheshreddykaanala94 2 жыл бұрын

Excellent sir....worth watching....tqsm ❤️❤️

@techTFQ 2 жыл бұрын

Thank you Mahesh :)

@XxLenasXx Жыл бұрын

This guys explanation is perfect and amazing

@srujanjajala 2 жыл бұрын

very helpful tutorial with realistic examples..

@techTFQ 2 жыл бұрын

Thank you buddy

@prajaktawagh2626 2 жыл бұрын

I am always eagerly waiting for your next vedio.. to learn new things.. keep going..

@techTFQ 2 жыл бұрын

Thank you for the support Prajakta 🙏🏼 Appreciate it ☺️

@anandhvdm6957 2 жыл бұрын

Sir, Could you please make a video on Index in SQL? How it will be useful in real time?

@techTFQ 2 жыл бұрын

Sure will do

@nikhilreddy4582 2 жыл бұрын

Totally different , easy to understand 👌

@techTFQ 2 жыл бұрын

Thank you 🙏🏼

@shaikusman536 Жыл бұрын

Just loved the way you teach....thanks a ton brother....Respect from INDIA.

@bedaprakash9609 11 ай бұрын

I just got to know He is from Malesiya , such really amazing contents not finding anywhere in youtube.

@hussainvali2577 2 жыл бұрын

I really like it. And I've interested on more like this. keep doing. appreciate ur hard work.

@techTFQ 2 жыл бұрын

Thank you Husain and noted

@benlong1062 11 ай бұрын

This video was really interesting. Your explanations are great! Thank you

@sauravrajchaudhary9036 2 жыл бұрын

Nice keep posting such videos . Please share video about complex topic in sql

@techTFQ 2 жыл бұрын

Thank you Saurav and will do

@Sunny-ok7dl Жыл бұрын

Amazing explanation, these 37 minutes were totally productive

@bhavanib8107 Жыл бұрын

great effort

@techTFQ Жыл бұрын

Thanks a lot

@sandeepkhawas3367 2 жыл бұрын

Borther thanks for your efforts..A quick question as i m not able to display data through coalesce function as displaying only transaction columns's comments suggest for the direction?

@techTFQ 2 жыл бұрын

sorry i dint get you.. are you saying coalesce is not working in your database? which database do you use? if oracle then you can use NVL instead