PHP MySQL :: Delete Data In a Database

The DELETE statement is used to delete records in a table.

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Delete Data In a Database

The DELETE FROM statement is used to delete records from a database table.

Syntax

DELETE FROM table_name WHERE some_column = some_value

Note: Notice the WHERE clause in the DELETE syntax. The WHERE clause specifies which record or records that should be deleted. If you omit the WHERE clause, all records will be deleted!

To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

Look at the following "Persons" table:

FirstName	LastName	Age
Peter	Griffin	35
Glenn	Quagmire	33

The following example deletes all the records in the "Persons" table where LastName='Griffin':

<?php $con = mysql_connect("localhost","peter","abc123"); if (!$con)   {   die('Could not connect: ' . mysql_error());   } mysql_select_db("my_db", $con); mysql_query("DELETE FROM Persons WHERE LastName='Griffin'"); mysql_close($con); ?>

After the deletion, the table will look like this:

FirstName	LastName	Age
Glenn	Quagmire	33

PHP MySQL :: Update Data In a Database

The UPDATE statement is used to modify data in a table.

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Update Data In a Database

The UPDATE statement is used to update existing records in a table.

Syntax

UPDATE table_name SET column1=value, column2=value2,... WHERE some_column=some_value

Note: Notice the WHERE clause in the UPDATE syntax. The WHERE clause specifies which record or records that should be updated. If you omit the WHERE clause, all records will be updated!

To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

Earlier in the tutorial we created a table named "Persons". Here is how it looks:

FirstName	LastName	Age
Peter	Griffin	35
Glenn	Quagmire	33

The following example updates some data in the "Persons" table:

<?php $con = mysql_connect("localhost","peter","abc123"); if (!$con)   {   die('Could not connect: ' . mysql_error());   } mysql_select_db("my_db", $con); mysql_query("UPDATE Persons SET Age = '36' WHERE FirstName = 'Peter' AND LastName = 'Griffin'"); mysql_close($con); ?>

After the update, the "Persons" table will look like this:

FirstName	LastName	Age
Peter	Griffin	36
Glenn	Quagmire	33

PHP MySQL :: WHERE clause

The WHERE clause is used to filter records.

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The WHERE clause

The WHERE clause is used to extract only those records that fulfill a specified criterion.

Syntax

SELECT column_name(s) FROM table_name WHERE column_name operator value

To learn more about SQL, please visit our SQL tutorial.

To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.

Example

The following example selects all rows from the "Persons" table where "FirstName='Peter':

<?php $con = mysql_connect("localhost","peter","abc123"); if (!$con)   {   die('Could not connect: ' . mysql_error());   } mysql_select_db("my_db", $con); $result = mysql_query("SELECT * FROM Persons WHERE FirstName='Peter'"); while($row = mysql_fetch_array($result))   {   echo $row['FirstName'] . " " . $row['LastName'];   echo "<br />";   } ?>

The output of the code above will be:

Peter Griffin