The UPDATE query in SQL is used to modify existing records in a table. It allows you to update specific columns' values in one or more rows of a table. It's important to note that the UPDATE query affects only the data, not the structure of the table.

Syntax

UPDATE tablename
SET column1 = "new_value", column2 = "new_value"
WHERE condition;

• tablename: The name of the table where the data will be updated.
• SET: Specifies the columns and their new values.
• WHERE: Determines which rows will be updated. If omitted, all rows in the table will be updated.

DATABASE IN USE:

Example 1: Update the Age of a Student

In this example, we'll update the age of a student named "Rishi Kumar" in the STUDENT table. We will change his age to 23:

import mysql.connector

# Connecting to the Database
mydb = mysql.connector.connect(
  host="localhost",
  database="College",
  user="root",  # Replace with your MySQL username
  password="your_password"  # Replace with your MySQL password
)

# Create a cursor object
cs = mydb.cursor()

# SQL query to update the age of a student
statement = "UPDATE STUDENT SET AGE = 23 WHERE Name = 'Rishi Kumar'"

# Execute the update statement
cs.execute(statement)

# Commit the changes to the database
mydb.commit()

# Disconnecting from the database
mydb.close()

Output:

Explanation:

• UPDATE query modifies the AGE column for the student with the name "Rishi Kumar".
• mydb.commit() ensures that the changes are saved to the database.
• connection is closed with mydb.close() to release resources.

Example 2: Correcting the Spelling of a Student's Name

In this example, we will correct the spelling of the student's name from "SK Anirban" to "S.K. Anirban" in the STUDENT table:

import mysql.connector

# Connecting to the Database
mydb = mysql.connector.connect(
  host="localhost",
  database="College",
  user="root",  
  password="your_password"  # Replace with your MySQL password
)

# Create a cursor object
cs = mydb.cursor()

# SQL query to update the name of the student
statement = "UPDATE STUDENT SET Name = 'S.K. Anirban' WHERE Name = 'SK Anirban'"

# Execute the update statement
cs.execute(statement)

# Commit the changes to the database
mydb.commit()

# Disconnecting from the database
mydb.close()

Output:

Explanation:

• UPDATE query changes the name "SK Anirban" to "S.K. Anirban".
• mydb.commit() ensures the changes are saved.
• The connection is closed after the operation.