SQLite Interview Questions

1) What is SQLite?

SQLite is a relational database management system which is self-contained, server-less and need zero configuration.

For more information: Click here

2) Who was the designer of SQLite?

SQLite was designed by D. Richard Hipp for the purpose of no administration required for operating a program.

For more information: Click here

3) What are the most important features of SQLite?

There are lots of features which make SQLite very popular:

SQlite is free of cost.
SQLite is server-less.
SQLite is flexible.
SQLite doesn’t need configuration.
SQLite is cross-platform.

For more information: Click here

4) What are the advantages of using SQLite?

SQLite is very light weight database.
Data storing is very easy and efficient.
SQlite is very easy to learn and use.

For more information: Click here

5) How would you create a database in SQLite?

In SQLite, sqlite3 command is used to create database.

Syntax:

For more information: Click here

6) How would you create a table in SQLite database?

CREATE TABLE statement is used to create a table in SQLite database. You have to define the columns and data types of each column while creating the table.

Syntax:

 CREATE TABLE database_name.table_name(   column1 datatype  PRIMARY KEY(one or more columns),   column2 datatype,   column3 datatype,   columnN datatype,   );   

For more information: Click here

7) How would you drop a table in SQLite database?

DROP TABLE command is used to delete or permanently drop a table from SQLite database.

Syntax:

For more information: Click here

8) How would you create an AUTOINCREMENT field?

For autoincrement, you have to declare a column of the table to be INTEGER PRIMARY KEY, then whenever you insert a NULL into that column of the table, the NULL is automatically converted into an integer which is one greater than the largest value of that column over all other rows in the table, or 1 if the table is empty.

9) What data types are supported by SQLite?

SQLite uses dynamic typing. Content can be stored as INTEGER, REAL, TEXT, BLOB, or as NULL.

10) How to insert data in a table in SQLite?

INSERT INTO statement is used to insert data in a table in SQLite database. There are two ways to insert data in table:

Method1:

Syntax:

 INSERT INTO TABLE_NAME [(column1, column2, column3,…columnN)]     VALUES (value1, value2, value3,…valueN);  

Method2:

Syntax:

For more information: Click here

11) How would you retrieve data from SQlite table?

The SELECT command is used to retrieve data from SQLite table. If you want to retrieve all columns from the table use SELECT * otherwise use the specific column’s name separated by commas.

Syntax:

 SELECT * FROM table_name;    Or  SELECT column1, column2, columnN FROM table_name; 

For more information: Click here

12) What is the use of UPADTE query in SQLIte?

The UPDATE query is used to modify the existing records in the SQLite table. You have to use the WHERE clause to modify a specific row otherwise all rows will be updated.

Syntax:

 UPDATE table_name   SET column1 = value1, column2 = value2…., columnN = valueN   WHERE [condition];  

For more information: Click here

13) How can you delete the existing records from a table in SQLite?

In SQLite, DELETE command is used to delete the existing records from a table. You should use the WHERE clause to choose the specific row otherwise all rows will be deleted.

Syntax:

For more information: Click here

14) What is the use of WHERE clause in CRUD statements?

WHERE clause is used to refer a specific row where the CRUD operation is executed. Without using WHERE clause all the rows will be affected.

For more information: Click here

15) What is the usage of AND & OR operators with WHERE clause?

AND & OR operators are used with WHERE clause to combine two or more than two conditions together.

Syntax:

 SELECT column1, column2, columnN    FROM table_name   WHERE [condition1] AND [condition2]…OR [conditionN]; 

For more information: Click here

16) What is the usage of LIKE operator with WHERE clause?

The LIKE operator is used to match text values against a pattern using wildcards. It uses two wildcards % and _ with string for matching with input.

Syntax:

For more information: Click here

17) What is the use of LIMIT clause with SELECT query?

LIMIT clause is used with SELECT statement when we want a limited number of fetched records.

Syntax:

For more information: Click here

18) Why is ORDER BY clause used with SELECT statement?

The ORDER BY clause is used to sort the fetched data in a specific order either ascending or descending.

Syntax:

 SELECT column-list    FROM table_name    [WHERE condition]    [ORDER BY column1, column2, .. columnN] [ASC | DESC];  

For more information: Click here

19) What is the use of SQLite GROUP BY clause?

SQLite GROUP BY clause is used to collect the same elements into a group. It is used with SELECT statement.

Syntax:

 SELECT column-list   FROM table_name   WHERE [ conditions ]   GROUP BY column1, column2….columnN   ORDER BY column1, column2….columnN   

For more information: Click here

Note: you can use GROUP BY and ORDER BY clauses together.

20) What is the use of DISTINCT clause in SQLite?

The DISTINCT clause is always used with SELECT statement. It is used to retrieve only unique records and restrict the duplicate entries.

It is used when the table has multiple duplicate records.

Syntax:

 SELECT DISTINCT column1, column2,…..columnN    FROM table_name   WHERE [condition]     

For more information: Click here

21) What is UNION operator? How does it work?

SQLite UNION Operator is used to combine the result set of two or more tables using SELECT statement. Both the tables must have same number of fields in result table.

Syntax:

 SELECT expression1, expression2, … expression_n   FROM tables   [WHERE conditions]   UNION   SELECT expression1, expression2, … expression_n   FROM tables   [WHERE conditions];  

For more information: Click here

22) What is UNION ALL operator? What is the difference between UNION and UNION ALL operator?

The UNION ALL operator is used to combine the result of two or more tables using SELECT statement. The unique difference between UNION and UNION ALL operator is that UNION operator ignores the duplicate entries while combining the results while UNION ALL doesn’t ignore duplicate values.

Syntax:

 SELECT expression1, expression2, … expression_n   FROM tables   [WHERE conditions]   UNION ALL   SELECT expression1, expression2, … expression_n   FROM tables   [WHERE conditions]; 

For more information: Click here

23) What is SQLite JOIN? How many types of JOINS are supported in SQLite?

SQLite JOIN clause is used to combine two or more tables in a database. It combines the table by using the common values of the both table.

There are mainly three types of JOINS supported in SQlite:

SQLite INNER JOIN
SQLite OUTER JOIN
SQLite CROSS JOIN

24) What is SQLite INNER JOIN?

SQLite INNER JOIN is simplest and most common join. It combines all rows from both tables where the condition is satisfied.

Syntax:

For more information: Click here

25) What is SQLite OUTER JOIN?

There are three types of OUTER JOINS:

Left outer join
Right outer join
Full outer join

But SQLite only supports left outer join. The SQLite left outer join returns all rows from left table and only those rows from the right table where the join condition is satisfied.

Syntax:

For more information: Click here

26) Explain SQLite CROSS JOIN.

The SQLite Cross join is used to match every rows of the first table with every rows of the second table. If the first table contains x columns and second table contains y columns then the resultant Cross join table will contain the x*y columns.

Syntax:

For more information: Click here

27) What is SQLite date and time () function?

SQLite date and time () functions are used to retrieve current date and time and also do calculations on the dates and time.

There are mainly 6 types of date and time () function in SQLite:

SQLite date() Function
SQLite datetime() Function
SQLite julianday() Function
SQLite now() Function
SQLite strftime() Function
SQLite time() Function

For more information: Click here

28) What is the use of date() function in SQLite?

The SQLite date() function is used to fetch the date and show it in ‘YYYY-MM-DD’ format.

Syntax:

For more information: Click here

29) What is the use of datetime() function in SQLite?

The SQLite datetime() function is used to retrieve current date and time in ‘YYYY-MM-DD HH:MM:SS’ format.

Syntax:

For more information: Click here

30) What is SQLite julianday() function?

A Julian Day is the number of days since Nov 24, 4714 BC 12:00pm Greenwich time in the Gregorian calendar. So, the julianday() function is used to return number of days since Nov 24, 4714 BC 12:00pm.

Syntax:

For more information: Click here

31) What is the use of SQLite now() function?

SQLite now is not a function. Instead of this, it is a timestring parameter which is used to fetch current date and time.

Syntax:

For more information: Click here

32) What is the usage of SQLite strftime() function?

SQLite strftime() function is used to fetch date and time and also perform time and date calculation.

Syntax:

For more information: Click here

33) What is the use of SQLite time() function?

SQLite time() function is used to fetch current time in ‘HH-MM-SS’ format.

Syntax:

For more information: Click here

34) What do you understand by SQLite aggregate functions?

SQLite aggregate functions are the type of functions where values of multiple rows are grouped together as input on certain criteria and form a single value as output.

There are many types of aggregate functions in SQLite.

For more information: Click here

35) What is SQLite MIN aggregate function?

SQLite MIN aggregate function is used to retrieve the minimum value of the expression.

Syntax:

For more information: Click here

36) What is SQLite MAX aggregate function?

SQLite MAX aggregate function is used to fetch the maximum value of an expression.

Syntax:

For more information: Click here

37) What is SQLite AVG aggregate function?

The SQLite AVG function returns the average value of the expression.

Syntax:

For more information: Click here

38) What is SQLite COUNT aggregate function?

The SQLite COUNT function is used to retrieve total count of an expression.

Syntax:

For more information: Click here

39) What is SQLite SUM aggregate function?

The SQLite SUM aggregate function is used to get the total summed value of an expression.

Syntax:

For more information: Click here

40) What is the difference between SQL and SQLite?

The main differences between SQL and SQLite are:

SQL is Structured Query Language while SQlite is a relational database management system mostly used in android mobile devices to store data.
SQL support stored procedures while SQLite does not support stored procedures.
SQL is server based while SQLite is file based.

41) What is SQLite Transactions?

Transaction specifies a unit of work that is performed against a database. The transaction?s properties are determined by ACID:

Atomicity: Atomicity is a property which specifies that all work units are successfully completed.

Consistency: It is used to ensure that the database changes states upon a successfully committed transaction.

Isolation: It facilitates you to operate transaction independently of and transparent to each other.

Durability: It ensures that the result or effect of a committed transaction persists in case of a system failure.

42) In which areas, SQLite is preferred most?

SQLite is preferred to work with:

Embedded devices.
Application file format.
Data Analysis.
Websites.
File archives.
Cache for enterprise data.
Server side database.
Internal or temporary databases.
Replacement for ad hoc disk files.
Experimental SQL language extensions.

43) What is the use of .dump command in SQLite?

The .dump command is used to make a SQLite database dump. Once you use the dump command all your data will be dumped forever and cannot be retrieved.

SQLite Interview Questions (2022)

SQLite Interview Questions

Note: you can use GROUP BY and ORDER BY clauses together.

Top 16 Shell Scripting Interview Questions (2022)

Top 50 TensorFlow Interview Questions (2022)

You may also like