PHP MySQLi SELECT

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The PHP SELECT statement is used to select data from a MySQLi table.

To select data from one or more tables.

Syntax:

SELECT column_name(s) FROM table_name

To select ALL columns from a table.

Syntax:

SELECT * FROM table_name

PHP mysqli_connect() function:

PHP mysqli_connect() function is used to open a new connection to the MySQL server. If the connection is established this function returns the resource, else it returns a null.

PHP mysqli_query() function:

PHP mysqli_query() function is used to perform a query against the MySQL database.

Syntax:

mysqli_query(connection,query,resultmode);

Connection: This is a required parameter which is used to specify the MySQL connection to use.

Query: This is an optional parameter which is used to specify the query string.

Resultmode: This is an optional parameter which is used to specify a constant either MYSQLI_USE_RESULT or MYSQLI_STORE_RESULT.

MYSQLI_STORE_RESULT is the default value of the resultmode. MYSQLI_USE_RESULT is used when a large amount of data need to be retrieved.

PHP mysqli_num_rows(mysqli_result $result):

The PHP mysqli_num_rows(mysqli_result $result) is used to retrieve number of rows in a table.

PHP mysqli_fetch_assoc(mysqli_result $result):

The PHP mysqli_fetch_assoc(mysqli_result $result) is used to retrieve rows of a table as an associative array. The column name of the table are the key of the array. As the number of rows ends, PHP mysqli_fetch_assoc(mysqli_result $result) function returns a NULL value in the array.

Example:

<!DOCTYPE html>
<html>
<body>
 
<?php
$phpconnect = mysqli_connect("localhost","Ben","Ben_password");
 
if (mysqli_connect_errno())
{
echo "Connection Failed; " . mysqli_connect_error();
}
 
$phpdatabase = "SELECT id, firstname, lastname, email FROM MyFriends";
$result = mysqli_query($phpconnect, $phpdatabase);
 
if ($result->num_rows > 0)
{
while($row = $result->fetch_assoc()) 
{
echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]." - Mail_ID: " . $row["email"]. "<br>";
}
} 
else 
{
	echo "No results";
}
 
mysqli_close($phpconnect);
?> 
 
</body>
</html>

Output:

id: 1 - Name: BEN DICHOSTA - Mail_ID: dichosta@example.com
id: 2 - Name: JOHN DEY - Mail_ID: john@example.com
id: 3 - Name: FLAIRA GATES - Mail_ID: gates@example.com
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