The DISTINCT clause is helpful when there is need of avoiding the duplicate values present in any specific columns/table. When we use distinct keyword only the unique values are fetched.

The cursor object is created by calling the cursor ( ) method of connection. The cursor is used to traverse the records from the result set.

The fetchall() method is used to fetch all rows from the database table.
result = cursor. fetchall()

To populate the table "INSERT" command is passed to SQLite."execute" method executes the SQL command to perform some action.
Example:
Sql_command =" " INSERT INTO student (Rollno, Sname, Grade, Gender, Average, birth_date) values (NULL, "Akshay", "B", "M", "87.8", "2001-12-12");" " cursor.execute(sql_command)

Create a connection using connect() method and pass the nanie of the database file.
Example:
#connecting to the database
connection = sqlite3.connect ("Academy.db")
#cursor
cursor = connection.cursor()

# Python code to demonstrate table creation and insertions with SQL
# importing module
import sqlite3
# connecting to the database
connection = sqlite3.connect ("Academy.db")
# cursor
cursor = connection.cursor ( )

Step 1: Import sqlite3
Step 2: Create a connection using connect o method and pass the name of the database File
Step 3: Set the cursor object cursor = connection. cursor ( )

Program: Display the records in descending order using python script
import mysqldb
db = mysqldb.connect ("local host", "user", "123", "organization")
cursor = db.cursor()
cursor.execute ("SELECT *FROM Employee ORDER BY Name DESC")
result = cursor.fetchall()
for row in results:
ENO = row[0], EmpName = row[1], EmpDept = row[2]
print ENO, EmpName, EmpDept
db.close()

The WHERE clause is used to extract only those records that fulfill a specified condition. In this example we are going to display the different grades scored by male students from "student table.
import sqlite3
connection = sqlite3.connect ("Academy.db")
cursor = connection.cursor()
cursor.execute ("SELECT DISTINCT (Grade) FROM student where gender = "M")
result = cursor.fetchall()
print(* result, sep ="\n")
Output:
('B,')
('A,')
('C,')
('D,')

fetchone() fetchmany() Returns the next row of a query result set or none in case there is no row left.
Using while loop and fetchone() method we can display all the records from a table one by one. Returns the next number of rows(n) of the result set.
Displaying specified number of records is done by using fetchmany():  

(i) Program to Display Name, city and Item Name of suppliers who do not reside in Delhi:
import mysqldb
db = mysqlkdb.Connect ("Supplier.db")
cursor = db.cursor()
cursor. execute ("'SELECT NAME, CITY, ICode FROM Supplier WHERE CITY <> "Delh")
db. commit()
result=cursor.fetchall()
print ("result, sep = "\n")
db. close()
(ii) Program to Increment the suppQty of Akila by 40:
import mysqldb
db = mysqldb.Connect ("ltem.db"')
cursor = db.cursor()
cursor. execute ("UPDATE Item SET Name = 'Akila' WHERE SuppQty = 235)
db. commit()
cursor. execute ("SELECT * FROM Item")
result = cursor.fetchall()
print ("result, sep ="\n")
db. close()

HAVING clause is used to filter data based on7the group functions. This is similar to WHERE condition but can be used , only with group functions. Group functions cannot be used in WHERE Clause but can be used in HAVING clause.
Example:
import sqlite3
connection = sqlite3.connect("Academy.db")
cursor = connection.cursorO
cursor.execute("SELECT GENDER,COUNT(GENDER) FROM Student GROUP BY GENDER HAVING COUNT( GENDER> 3")
result = cursor.fetchall( )
co = [i[o] for i in cursor. description]
print(co)
print(result)
Output:
['gender', 'COUNT(GENDER)']
[('M', 5)]

Creating database:
Sql_command = " "
CREATE TABLE Hardware (
lcode INTEGER PRIMARY KEY.
ltem_Name VARCHAR(20),
Rate DEClMAL(5,2));" "
Program: To display the records using fetchmany()
import sqlite3
connection = sqlite3.connect ("Material.db")
cursor = connection.cursor()
cursor. execute ("SELECT * FROM Hardware")
print("fetching first 5 records:")
result = cursor.fetchmany(5)
print(result)
Output:
fetching first 5 records:
[(1003, 'Scanner', "10500'), (1004, 'Speaker', '3000'), (1005, 'Printer', '8000'), (1008, 'Monitor', '15000'),
(1010, 'Mouse', '700')]

(i) SQLite is a simple relational database system, which saves its data in regular data files or even in the internal memory of the computer.
(ii) It is designed to be embedded in applications, instead of using a separate
database server program such as MySQL or Oracle.
(iii) SQLite is fast, rigorously tested, and flexible, making it easier to work. Python
has a native library for SQLite.
To use SQLite,
Step 1: import sqlite3
Step 2: create a connection using connect() method and pass the name of the database file
Step 3: Set the cursor object cursor = connection. cursor()
(iv) Connecting to a database in step 2 means passing the name of the database to be accessed. If the database already exists the connection will open the same. Otherwise, Python will open a new database file with the specified name.
(v) Cursor in step 3 is a control structure used to traverse and fetch the records of the database.
(vi) Cursor has a major role in working with Python. All the commands will be executed using cursor object only.
(vii) To create a table in the database, create an object and write the SQL command in it.
Example: sql_comm = "SQL statement"
(viii) For executing the command use the cursor method and pass the required sql command as a parameter. Many number of commands can be stored in the sql comm and can be executed one after other.
(ix) Any changes made in the values of the record should be saved by the commend "Commit" before closing the "Table connection" .