UPDATE command is used to modify an existing record in the table.
Syntax:-
UPDATA table_name
SET column_1=new_value_1,
column_2=new_value_2,
column_3=new_value_3
...................
...................
column_n=new_value_n
WHERE [CONDITION]
Example:-
Suppose you have two records in the employees table
SELECT * FROM employees
Output:-
+----+------------+-----------+----------------+------------+
| id | first_name | last_name | email | address |
+----+------------+-----------+----------------+------------+
| 1 | Virat | Kohli | virat@abc.com | Delhi |
| 2 | rohit | Sharma | rohit@abc.com | Mumbai |
+----+------------+-----------+----------------+------------+
Apply WHERE Condition
FIRST CASE:- Now, You want to update the address of Virat from Delhi to Mumbai
UPDATE employees SET address='Mumbai' where id=1
Now, check the table
+----+------------+-----------+----------------+------------+
| id | first_name | last_name | email | address |
+----+------------+-----------+----------------+------------+
| 1 | Virat | Kohli | virat@abc.com | Mumbai |
| 2 | rohit | Sharma | rohit@abc.com | Mumbai |
+----+------------+-----------+----------------+------------+
Without WHERE Condition
SECOND CASE:- If you do not use where condition then the record will be update in all rows.
Example:- If you want to update email of rohit@abc.com to rohitsharma@abc.com without where condition.
UPDATE employees SET email='rohitsharma@abc.com'
Now check the updated results in the employees table
SELECT * FROM employees
Output:-
+----+------------+-----------+----------------+------------+
| id | first_name | last_name | email | address |
+----+------------+-----------+----------------+------------+
| 1 | Virat | Kohli | rohitsharma@abc.com | Mumbai|
| 2 | rohit | Sharma | rohitsharma@abc.com | Mumbai|
+----+------------+-----------+----------------+------------+