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Top 50 SQL Interview Questions and Answers Part 1

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Best Buy Links (affiliate): SQL The Complete Reference https://amzn.to/2NAfr2G SQL Cookbook (Covers SQL Server, PostgrSQL, Oracle, MySQL, And Db2) https://amzn.to/2MhU6Xl Beginning SQL Queries https://amzn.to/2NzaAPj SQL, PL/SQL the Programming Language of Oracle https://amzn.to/2QjIyWH SQL in easy steps https://amzn.to/2x73t6G T-SQL Fundamentals https://amzn.to/2NywZfC Microsoft SQL Server 2012 Step By Step https://amzn.to/2O8BMBI ----------------------------------- SQL INTERVIEW QUESTIONS AND ANSWERS on this link - https://viden.io/knowledge/sql-interview-questions-and-answers DBMS notes-https://viden.io/knowledge/dbms-interview-q-a
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Text Comments (85)
Wakola Tamiru (19 hours ago)
SQL language is avast Technology than MS Access DBA
365 Data Science (1 day ago)
Here are some frequently encountered SQL interview question, and my top tips to answering them: 1. What is SQL? SQL, Structured Query Language, is a programming language designed for working with databases. Some people, however, argue that it is not exactly a programming language since it has not been created with the notion of using features of procedural languages, such as conditional statements or “for” loops. These people insist on calling SQL a coding language because it is only about executing commands for querying, creating, inserting, updating, and deleting data in a database. Nonetheless, the most important thing is to know what the domain of SQL is. 2. What is a Database? What is a DBMS? A database is data stored on a computer and ordered in a way that makes it easy to access and manipulate. a database management system – DBMS is the software tool that allows users to interact with the data stored in the database. You could conclude by explaining there are two types of database management systems – relational and non-relational. SQL is a language, designed only for working with relational DBMSs. Such questions are usually asked in the beginning of the interview so that you can start preparing for the difficult ones. 3. What is the difference between DDL, DML, DCL, and TCL? First of all, let’s explain what there acronyms stand for: “L” stands for “Language” in all of them. And this must help you remember that these are the four categories in which the SQL commands have been separated into. DDL stands for Data Definition Language and includes the commands that allow you to CREATE, DROP, ALTER, and TRUNCATE data structures. DML involves commands for manipulating information. It actually means “Data Manipulation Language”, and gives the possibility to SELECT, INSERT, UPDATE, and DELETE data. it is this part of the language you will most use at work, if you are using SQL in the field of data science or business intelligence. DCL, Data Control Language, consists of commands that are usually used by database administrators. This one allows programmers to GRANT and REVOKE rights defining how much control you can have over the information in the database. Similarly, TCL, which is the Transaction Control Language, also includes the commands applied by database administrators. These command ensures that the danger of suffering from data loss is minimal. 4. What is the point of using a foreign key constraint? The foreign key constraint comprises a set of rules, or limits, that will ensure that the values in the child and parent tables match. Theoretically, the foreign key constraint will maintain the referential integrity within the database. 5. Define and provide an example of using an inner join. Obviously, you must be aware that joins are one of the most frequently used tools in SQL, regardless of your job role. Particularly if you are working in the sphere of business intelligence, your work will be centred around understanding SQL joins in depth. So, an SQL join is a tool that allows you to construct a relationship between objects in your database. Consequently, a join shows a result set containing fields derived from two or more tables. For instance, assume that in one table you have data about the customer ID and fields related to the sales a customer has made, and in the other, you have data about the customer ID and their private information, such as first and last name and email address. Therefore, an inner join allows you to obtain an output containing information from both tables only for the customer IDs found in the two tables that match. Provided that you set the customer ID field to be a matching column, of course. 6. What is the difference between MySQL and PostgreSQL? How about between PL/SQL and SQL? The interviewers ask these questions as they want to find out how much you are acquainted with the fact that SQL has a few versions, each carrying specific features. You could say that MySQL and PostgreSQL are just two versions of the Structured Query Language. Since you’ve just been asked about joins, you could mention that PostgreSQL supports outer joins, while MySQL doesn’t – you’ll need to use UNION or UNION ALL to emulate an outer join in MySQL. This way you could even impress the interviewers with extra knowledge in this subject. PL/SQL is not a version of SQL, however, and that’s the tricky part of the question. PL/SQL is a complete procedural programming language and its scope of application is different. It is not strictly related to relational databases. 7. What is an SQL View? Your potential future employers may want to give a toned-down SQL interview question. That’s why they might ask a general question. A view is a virtual table whose contents are obtained from an existing table or tables, called base tables. The retrieval happens through an SQL statement, incorporated into the view. In other words, you can think of a view object as a view into the base table. The view itself does not contain any real data; the data is electronically stored in the base table. The view simply shows the data contained in the base table. Source: https://bit.ly/2Fe6x4Q Good luck! Best, 365 Data Science Online educational career website https://365datascience.com/
Calvin F (6 days ago)
Come on, you don't ask such questions in interviews. Just throw him a table and ask him to write the sql to retrieve what you wanted.
Jeyhun Aliyev (20 days ago)
anisur rahman (24 days ago)
Great work dada. It is very helpfull
Chitra Kanojiya (1 month ago)
plzz send me pdf id : [email protected]
Shivananda Dodamani (1 month ago)
Thanks sir, your explaination is very good,, i think little more detailed explaination is required
Crazy4 DB (1 month ago)
Appreciable efforts. We may get introduced with each other, also a corporate trainer in Oracle
Anit Andrews (2 months ago)
Thank you so much subscribed
NOOF (2 months ago)
I have an internship interview and I don't know from where to start my reserches, your video is a life saver!!! Thank you man
peter john (3 months ago)
I completely agree with Malike Eyakwe !!! It says in India When Elefant walking on the street wild dogs are barking, Elefant even doesn't care and keep walking !!! Keep it up
usbranded cosmetics (3 months ago)
very good info
Harsh Bhatnagar (3 months ago)
would have been a better video if real/live example demos were provided.
Burhan sheikh (3 months ago)
I want know that difference between data and database
Venkatesh V (1 month ago)
Data constitutes text document word, pdf etc, multimedia files and other types of electronic information that can be stored in devices like drives, and also in cloud which is a network of large storage servers. Whereas database is not necessarily a storage area, it much like an index of a big textbook, it can store some data, but it mainly consits of metadata which consist of details related to data. With the help of metadata we can conveniently manage the data by adding, updating, retrieving etc.
Komala Narpala (3 months ago)
This is what I know...hope it helps you..Data is a processed information.information and data are different.information contains raw . It becomes useful data when it gets processed.database is used to store the data
Krishna Algot (3 months ago)
plz sir send me pdf file mail id : [email protected]
Des Troya (5 months ago)
I'm going to apply for a job and they will ask me "what is a database"? Seriously I don't think so
aaradhy sharma (4 months ago)
They can depends on your job plus on mood of interviewer
mitesh ranka (6 months ago)
Any body also think vedio subject should has data warehouse in it
Hannah Shiny (6 months ago)
extreamly good
The Beetroot Channel (6 months ago)
It's really informative sir! I am truly following the videos on this channel also it's inspired me to open YouTube channel of my own .. thanks for inspiring
LearnEveryone (6 months ago)
all the best ....
Venkata Krishnudu (6 months ago)
Pls send me PDF file
Chitra Kanojiya (1 month ago)
send me too pdf file id: [email protected]
Karen Smith (4 months ago)
MADHU CHANDER Jaina (4 months ago)
search in guru 99 top 50 interview questions
Parishi Gujarathi (4 months ago)
send me the pdf on the mail. id: [email protected]
Roshni Siddiquee (6 months ago)
Send me pdf on email [email protected]
Harsh Vardhan Dewari (6 months ago)
thank YOU
LearnEveryone (6 months ago)
thanks ...HVD......:)
Krupa varam (7 months ago)
Very clear n good explanation Sir..tnq
LearnEveryone (6 months ago)
welcm Ak...:)
Malike E Eyakwe (9 months ago)
I can't believe 198 people hate this video,you haters are so mean.He is helping us for free and u dislike, can you teach?Please learn to appreciate
Rahul Rachh (14 days ago)
410 bhai!!!
Manish Kharkwal (1 month ago)
355 now
The Beetroot Channel (6 months ago)
I agree completely. As he helps we ought to thanks not dislike
ob882 (6 months ago)
242 dude
vinay ss (6 months ago)
235 bro
Shibajyoti Sinha (9 months ago)
Life is a cup cake seems like ahhahaa
ALLCPL (9 months ago)
Al Schwartz (9 months ago)
this would be so much better if in english
Miss Ramz (2 months ago)
People like you used to annoy the sh#t out of me when i used to work in tech support.
Alex Natic (2 months ago)
krakow47 (4 months ago)
+Fishing and Photography by Shaon wahahahahahah
It IS in English.
Priya S (11 months ago)
Useful for fresher and also Experienced person. Regards http://www.greenstechnologys.com/
Aakula Lavanya (11 months ago)
tq sir...ur explanation is very good
Rahul Kumar (1 year ago)
SQL plsql.
Renu Saraswat (1 year ago)
How split the data and display the output in different different columns. For ex- Hina Bhatt is a name in name column we want to show Hina in a different column and Bhatt in different column
Small clips (1 year ago)
From sql server 2016 onwards you can use string_split Else You have to write your own sql Ex: Select LEFT('hina bhatt', CHARINDEX(',', 'hina bhatt') - 1) Similarly for last part use substring
Small clips (1 year ago)
Sonu Hemke which split function ? String_split was introduced from 2016 onwards .. before that you have to write a custom function.
Sonu Hemke (1 year ago)
Use the split function
shiva prasad (1 year ago)
Good one Sir,Can you please send me PDF document([email protected])
LearnEveryone (1 year ago)
its in description...
Alpesh Kathiriya (1 year ago)
Thanks.. please pdf file send me email: [email protected]
ADITYA KAR (1 year ago)
Kya baat kya baat kya baat😍🙄
Sanjay Mergal (1 year ago)
[email protected] please send pdf
S.karimulla shaik (1 year ago)
sir please send me the pdf file to my gmail i.e [email protected]
Keerthi Kumar GP (1 year ago)
Please send PDF file to [email protected]
T VENKATESH KUMAR (1 year ago)
sir are u that chemistry sir
Lala (1 year ago)
shiva kumar (1 year ago)
nice add:a5 man,boy,mlritm
Balasaheb Paul (1 year ago)
if possible try to give us that questions list which are in videos, in the video description
LearnEveryone (1 year ago)
its in the description bala...
Balasaheb Paul (1 year ago)
it was very helpful for interview
ALLCPL (10 months ago)
sai krishna (1 year ago)
plz send interview questions [email protected]
Apoorva Mathur (1 year ago)
pls mail me the PDF [email protected]
LearnEveryone (1 year ago)
its thr in description apoorva...
rutu patel (1 year ago)
plzz could you make video of pl/sql and dbms more information (details)
Nagesh chinna (1 year ago)
thank you sir..... please sir pdf file send me email: [email protected]
Nagesh chinna (8 months ago)
Suganya Sri (1 year ago)
R u got pdf file?
Sandesh VN (1 year ago)
Sir, can you give me the PDF file of these questions to [email protected]
Singari Manikanta (1 year ago)
this only on sql.plz give interview wise topic.
Ganesh Chittalwar (1 year ago)
plz could you make vdo of pl/sql ans sql more details
Sir, can you give me the PDF file of these questions. [email protected]
robin mitrani (1 year ago)
wah wah wah!!!
Ashutosh Patel (1 year ago)
thanks alot
Krishna Mullapudi (1 year ago)
thank you very much .

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