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.

Execute (sql[, parameters]) :
(i) Executes a single SQL statement. The SQL statement may be parameterized (i.e. placeholders instead of SQL literals).
(ii) The SQlite3 module supports two kinds of placeholders: question marks? ("qmark style") and named placeholders: name ("named style").

cursor. description contains the details of each column headings. It will be stored as a tuple and the first one that is 0(zero) index refers to the column name. Using this command you can display the table's Field names.

(i) The WHERE clause can be combined with AND, OR, and NOT operators.
(ii) The AND and OR operators are used to filter records based on more than one condition.

(i) The ORDER BY clause can be used along with the SELECT statement to sort the data of specific fields in an ordered way.
(ii) It is used to sort the result-set in ascending or descending order.

SQlite_master is the master table which holds the key information about your database tables.

The reason behind the triple quotes is sometime the values in the table might contain single or double quotes.

(i) A cursor in SQL and databases is a control structure to traverse over the records in a database. So it's used for the fetching of the results.
(ii) 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)

If a column of a table is declared to be an INTEGER PRIMARY KEY, then whenever a NULL is used as an input for this column, the NULL will be automatically converted into an integer which will be one larger than the highest value so far used in that column.

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()

Users of database can be human users or programmers, other programs or applications.

(i) DISTINCT
(ii) WHERE
(iii) GROUP BY
(iv) ORDER BY.
(v) HAVING

(i) "SELECT" is the most commonly used statement in SQL.
(ii) The SELECT Statement in SQL is used to retrieve or fetch data from a table in a database.
(iii) The syntax for using this statement is "Select * from table_name" and all the table data can be fetched in an object in the form of list of lists. List the classes used in

(I) COUNT ( ) function returns the number of rows in a table.
(ii) AVG ( ) function retrieves the average of a selected column of rows in a table.
(iii) SUM ( ) function retrieves the sum of a selected column of rows in a table.
(iv) MAX( ) function returns the largest value of the selected column.
(v) MIN( ) function returns the smallest value of the selected column.

Aggregate functions are used to do operations from the values of the column and a single value is returned.
(i) COUNT ( )
(ii) AVG ( )
(iii) SUM ( )
(iv) MAX ( )
(v) MIN ( )

# 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 ( )

(i) The SELECT statement can be used along with GROUP BY clause.
(ii) The GROUP BY clause groups records into summary rows. It returns one records for each group.
(iii) It is often used with aggregate functions (COUNT, MAX, MIN, SUM, AVG) to group the result -set by one or more columns.

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()

Db: Organization.db
Table name: Employee
Column: Eno, EmpName, Esal, Dept
Program:
import mysqldb
db = mysqldb.connect("localhost, "user", "123", "organization")
cursor= db.cursor()
Cursor.execute ("SELECT *FROM Employee")
results = 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,')

(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.
Advantages:
SQLite is fast, rigorously tested, and flexible, making it easier to work.
Python has a native library for SQLite.

(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()

Program:
import mysql db
db = mysqldb.connect ("local host", "user", "123", "organization'")
cursor = db.cursor()
item table creation
database: ABC, table: Item, lcode: int, ItemName: Char
Rate: int. Record: 1008, Monitor: 15000
cursor.execute ("Create table item(icode int, item Name char (25), Rate int"));
db.close
cursor. execute ("insert into item values ("1008", 'Monitor', '15000" ));
db.commit()

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" .