In this tutorial, we will learn how to filter rows from the fetched resultset, or update a specific row, or delete a specific row from a MySQL table using the
WHERE clause to specify the condition to find the record/row of data on which the operation is performed.
WHERE clause is nothing but a way to provide a condition(or multiple conditions) to the SQL engine, which is applied on the query resultset to filter out the required records of data.
We have already used the
WHERE clause in our previous tutorials:
If you want to select data from a table based on some condition then you can use
WHERE clause in the
WHERE clause is mainly used for filtering the rows from the result set.
It is helpful in fetching, updating, and deleting data from the MySQL Table.
The syntax of using
WHERE clause in
SELECT statement is as follows:
SELECT column_name FROM table_name WHERE condition;
The above syntax is useful in fetching the records on the basis of some conditions.
Below we have an example where we will fetch the row having rollno = 2 from our students table(from the Python MySQL create table tutorial):
import mysql.connector as mysql ###First create a connection between mysql and python db = mysql.connect( host = "localhost", user = "yourusername", passwd = "yourpassword", database = "studytonight" ) # now create a cursor object on the connection object # created above by using cursor() method cursor = db.cursor() ## defining the Query query = "SELECT * FROM students WHERE rollno= 2" ## getting records from the table cursor.execute(query) ## fetching all records from the 'cursor' object records = cursor.fetchall() ## Showing the data for record in records: print(record)
The output of the above code will be:
('Peter', 'ME', 'Noida', 2)
Here is the snapshot of the actual output: