In other articles I have already given the multiple SQL interview questions. This article is useful specially to the fresher who wants to learn SQL step by step and who wants to perform good in the interviews. The article will give you brief about the SQL interview questions for freshers and the questions regarding the same.
1.What is SQL?[100 % asked Latest SQL Interview Questions for freshers ]
SQL Stands for Structured Query Language which is specially designed to communicate with databases.SQL pronounced as Sequel is very widely used language in most of the database management systems like Oracle,MySQL,PostgreSQL etc.SQL provides us a simple and efficient way of reading,writing,executing the data from the system.this is one of the SQL Interview Question ever asked in interviews
2.What is the use of NVL function in Oracle?[80% asked SQL Interview Question ]
NVL function is most important function to replace null value with another value.
Example: select NVL(null,'Amit') from dual; which will give you output as Amit.
3.What is Unique Key? [ 90% asked SQL Interview Questions for freshers ]
Unique key is nothing but the columns which are uniquely identifies the values.There are more than one unique keys for each table.The Entry of Null value is allowed in Unique key.Oracle does not permit you to create primary key and unique key on same column.
Syntax: Create table Table_name (Column_name1 Datatype[null/not null], Column_name Datatype[null/not null]....... Constraint constraint_name Unique(uc_col1,uc_col2..));
4.What is difference between Unique Key Constraint and Primary Key Constraint?[80% asked SQL Interview Questions for freshers]
Primary Key constraint:
1.Primary key will not accept the null values in the table column.
2.Primary is basically used to identify the unique records in the table.
3.We have only one primary key per table.
Unique Key Constraint:
1.Unique key accepts the null values in the table.
2.The main task of unique key is it is used to remove duplicate values from the table with exception of null entry.
3.We will have more than 1 unique keys on a single table.
5.What is difference between varchar and varchar2 datatype?
As an example ,Varchar can store up to 2000 bytes and varchar2 can store up to 4000 bytes of memory space.Varchar will occupy the space for null values whereas varchar2 can not occupy the space for null values.So varchar2 is good to use not to face performace related problems.varchar2 is faster than varchar datatype.
6.How to represent comments in oracle?
There are following 2 ways for commenting in oracle:
1.Single Line comment: Two dashes (–) before begining of the line
2.Multiline comment/Block comment:When user wants to comment multiple line /* */ operators are used.
7.What is raw datatype?[90% asked in SQL Interview Questions]
The example for the same is below , Raw datatype is used to store values in binary data format.There are 2 types of RAW datatype.1.Raw 2.Long Raw. Long raw datatype is used to store graphics,sound documents.Raw datatype is variable length datatype like varchar2 but basically it only stores data in 1 ‘s and 0’s means binary data format.
8.What is ROWID & ROWNUM?(90 % asked in SQL Interview Question)
ROWID is nothing but the physical address given to that row which is in hexadecimal format.ROWNUM is nothing but the logical sequence given to the row of that column.
[click here for detailed description]
9.What are views in SQL?Explain types of Views in SQL?(Asked in almost every SQL Interview Questions)
Views are nothing but the logical structure of the table where we can fetch the data from different tables or same table.
There are 2 types of views in Oracle:
1.Simple View:Simple view has been created on only a single table.
2.Complex view:Views which are created using more than 1 table which has joins clauses are known as complex views.
[Click here to get more information on views]
10.What is Materialized View in SQL?
Materialized view is also logical structure of one or more table in which data is stored physically in the view.Data has been stored physically in materialized view so data retrieval is faster as compare to simple view.
[Click here to get more information on materialized view]
11.Why to use SQL? [90% asked SQL Interview Questions ]
SQL is structured query language which is used for manipulation of data.There are following reasons why to use SQL:
Allows users to access data in relational database management systems.
Allows users to define the data in database and manipulate that data.
Allows users to create and drop databases and tables.
Allows users to create view, stored procedure, functions in a database.
Allows users to set permissions on tables, procedures, and views.
12.What is difference between Truncate ,Drop and DELETE?
1.Drop command is DDL command which is used to delete the object from the database.
2.We can not use the “ROLLBACK” after using drop command.
3.Drop command free’s the space of database object.
4.Drop table table_name;
1.Truncate command is DDL command which is used to truncate the data from the database table.
2.We can not use the “ROLLBACK” after using Truncate command.
3.It free’s the space of database object but the structure remains same and memory of structure also remains same.
4.Truncate table table_name;
1.Delete command is DML command which is used to delete the records from table.
2.We can use Rollback to Rollback the records from the table.
3.Delete command not free’s the memory space.
4.Delete table table_name where condition;
13.Explain About DDL Statements of SQL?
DDL – DDL stands for Data Definition Language:
|CREATE||Creates a new table, a view of a table, or other object in database|
|ALTER||Modifies an existing database object, such as a table.|
|DROP||Deletes an entire table, a view of a table or other object in the database.|
14.What is DML in SQL.Explain DML Statements in Details?
DML stands for Data Manipulation Language:
|INSERT||Creates a record|
15.What is Database?[90% asked SQL Interview Questions]
- It is a collection of Inter-Related data. Records the data in HDD (Permanent Memory).
- Inter-Related data means relation among data values
- Objective of DB is to record data & save it for future use.
16.What is RDBMS?
RDBMS stands for Relational DataBase Management System. RDBMS is the basis for SQL, and for all modern database systems like MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access.
A Relational database management system (RDBMS) is a database management system (DBMS) that is based on the relational model as introduced by E. F. Codd.
17. What are tables and Fields?
A table is set of data which is organized in to specific structured manner.Table is made up of combination of columns and rows.A table has specified number of column called fields but can have any number of rows which is called record.
|Name(Field 1)||Salary(Field 2)|
18.Explain me about SQL joins?
CLICK HERE TO GET ANSWER IN DETAILS
Join is nothing but connecting 2 tables to fetch the records from 2 or more different tables.There are following types of joins in SQL:
Inner join retreives the records which are common between 2 or more tables.
Outer join retrieves the common records from the table as well as uncommon records from Left or right table.
2.1.Left outer join:
When user needs to fetch all data from left table and common records from left and right table then the join is called as left outer join.
2.2.Right outer join:
When user needs to fetch all data from right table and common records from left and right table then the join is called as right outer join.
2.3.Full Outer Join:
When user needs to fetch the data from both the tables and common records from both of the tables.
3.Cross join/Cartesian join:
When each and every record is connected to each and every record from other table then it is called as cross join or Cartesian join.
19.What is Views in SQL?(Asked in almost every SQL Interview Questions)
View is nothing but the virtual structure which is been created from using single table or multiple tables.If the logical structure is created from single table then it is called as Simple view.If logical structure is created using multiple tables using joins then it is called as Complex View.
Click here to get more information about views
20.What is index and what are types of indexes?[80% asked SQL Interview Questions ]
Indexing is nothing but the performance tuning mechanism which allows the fast retrieval of the records from table.
Following are types of indexes:
2.Bit Map indexes
5.Non Clustered Indexes
Click here to get more information on Indexes
Hope you like this article on SQL Interview Questions for fresher.If You want the PDF for these interview questions kindly comment in comment section..
55 Replies to “What are Top 20 SQL interview Questions for Freshers?”
I need a PDF of this questions
I sent you interview questions PDF on your mail id.
Plz send me sir.I have interview ..my mail id….email@example.com
Kindly check your mailbox..I sent you interview questions.
sir send me mostly interview questions only sql queries for fresher
Sure Harish!! I sent you the SQL interview questions.
It would be great if you send pdf of all interview questions including(concepts+queries).
Thank you so much for your hard work.
Sure !! I will send you interview questions on your mail id!!
sir, please send the pdf
Hi sir can u email this SQL question. PDF
Kindly check your mailbox.
sir can u please send me some basic to advance interview questions regarding sql
Sure Tejesh!!! I will send you interview questions.
Can u help me with real world scenario’s so that I can practice better
Can u email me with some interview questions with 1 yr exp in sql server
I have mailed you interview questions.You can check all types of queries in following link :
Please mail the pdf of interview qsns and some complex sql queries with answers
sir pls sent pdf to my mail.
Sir send me the PDF of Freshers interview questions asked in oracle.the therory and the quaries both.and sir what are the topics I have to cover for SQL interview as a fresher
I sent you interview questions on your id.
AMIT thanks for this question can u plz send me on e on my mail I’d.my mail I’d is firstname.lastname@example.org
I have sent you SQL Interview questions on your mail id!!
Regards and thanks,
Hi dude. Please to send the SQL related documents to my mail “email@example.com”
I have sent you the Interview questions…
please send me the pdf
Please send me the most frequently asked theoretical sql questions as well as queries asked in interviews. Also if you have any sql MCQs asked in written exams please do send me.
Sure Buddy!! I sent you interview questions 🙂
Can you please send SQL interview questions for free to my email ID ?
I’ll be so thankful if you could. 🙂
please send me the pdf
Sent youy interview questions..
Most Welcome Buddy!!
Hi, This is PARUSHURAM. Please SQL Server Experience interview FAQs PDF file .please send me firstname.lastname@example.org
Kindly check your inbox for the same.
Hello Sir, can you share the PDF of Freshers interview questions asked in dbms(therory and the quaries both)
sure ankita .I have sent you the PDF on your respective mail id.
I saw u forwarded pdf file of SQL questions and answers, Can u send me too plz.
I really appreciate ur help.
Sure Megha..Kindly check your inbox..
hi please provide me the pdf of it
Sure Charu ..Will provide you pdf..
pls share pdf…..i have interview in next week
Sure chaitanya..Kindly check your inbox for the same..
hello,i need pdf of this.
Sure Haribal..Check your inbox
tomorrow i have an interview can you share the PDF of Freshers interview questions asked in DBMS theory and the Queries both.
I sent you interview questions.
Can you please send me the interview questions and answers for 3+yrs experience candidates for pl/sql stream.
Thanks in advance.
Sure Harsh..Kindly check your inbox.
Pls can u share me pdf
Sure Kavita. Kindly check your inbox .
Sir, plz provide me pdf of all important topics in sql and database with study materials
Sure Ashish . I sent you SQL interview questions for fresher as well as experienced 🙂
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