PHP and MySQL 30: query select

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Happy Coding

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In this post, we will learn about how to use query SELECT in PHP for retrieve data from database MySQL, with 3 ways:

1. MySQLi procedural
2. MySQLi object-oriented
3. PDO

For known, how to connect to database, can be learned in here

Insert query is used for insert data or record into database

Syntax:

    SELECT column1, column2, column3 
    FROM table_name;

using wilcard (*) for select all column

    SELECT *
    FROM table_name;

Example:

    $sql  = "SELECT id, firstname, lastname ";
    $sql .= "FROM users " ;

    $sql  = "SELECT * ";
    $sql .= "FROM users " ;

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And, for execute the query, we will use 3 ways:

1. MySQLi¹ procedural

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Execute query using mysqli::query² and get a $result:

    $result = mysqli_query( $connection, $sql );

Display data using mysqli_result::fetch_assoc³, alternative using mysqli_result::fetch_object⁴:

    echo "<pre>";

    echo "No \t";
    echo "ID \t";
    echo "Firstname \t\t";
    echo "Lastname \n";

    $no = 1; /* variabel $no */

    /* loop while */
    while ( $row = mysqli_fetch_assoc($result) )
    {

        echo $no . "\t";
        echo $row['id'] . "\t";
        echo $row['firstname'] . "\t\t";
        echo $row['lastname'] . "\n";

        $no++; /* increment */

    }

    echo "</pre>";

Close connection using mysqli::close⁵:

    mysqli_close($connection);

Source Code:

• repl.it/antelove19/MySQLi/procedural/select

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2. MySQLi¹ object-oriented

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Execute query using mysqli::query² and get a $result:

    $result = $connection->query($sql);

Display data using mysqli_result::fetch_object⁴:

    echo "<pre>";

    echo "No \t";
    echo "ID \t";
    echo "Firstname \t";
    echo "Lastname \n";

    $no = 1; /* variabel $no */

    /* loop while */
    while ( $row = $result->fetch_object() )
    {

        echo $no . "\t";
        echo $row->id . "\t";
        echo $row->firstname . "\t\t";
        echo $row->lastname . "\n";

        $no++; /* increment */

    }

    echo "</pre>";

Close connection using mysqli::close⁵:

     $connection->close();

Source Code:

• repl.it/antelove19/MySQLi/object-oriented/select

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3. PDO⁶

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Execute query and get a $result:

    $result = $connection->query($sql);

Display Data:

    echo "<pre>";

    echo "No \t";
    echo "ID \t";
    echo "Firstname \t";
    echo "Lastname \n";

    $no = 1; /* variabel $no */

    /* loop foreach */
    foreach ( $result as $row  )
    {

        echo $no . "\t";
        echo $row->id . "\t";
        echo $row->firstname . "\t\t";
        echo $row->lastname . "\n";

        $no++; /* increment */

    } 

    echo "</pre>";

Close connection:

    $connection = null;

Source Code:

• repl.it/antelove19/PDO/select

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Thank for reading :)

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1. php.net, "MySQL Improved Extension", accessed on date 21 december 2019 and from https://www.php.net/manual/en/book.mysqli.php ↩

2. php.net, "mysqli::query", accessed on date 22 december 2019 and from https://www.php.net/manual/en/mysqli.query.php ↩

3. php.net, "mysqli_result::fetch_assoc", accessed on date 23 december 2019 and from https://www.php.net/manual/en/mysqli-result.fetch-assoc.php ↩

4. php.net, "mysqli_result::fetch_object", accessed on date 23 december 2019 and from https://www.php.net/manual/en/mysqli-result.fetch-object.php ↩

5. php.net, "mysqli::close", accessed on date 21 december 2019 and from https://www.php.net/manual/en/mysqli.close.php ↩

6. php.net, "PDO::__construct", accessed on date 21 december 2019 and from https://www.php.net/manual/en/pdo.construct.php  ↩