php-Update table by selecting multiple primary keys and perform two different actions

Table beside which there is a check box and at the bottom of the table two buttons which has to perform dirrent action

action1- Change the status of selected rows.

action2- Send the selected rows to an email address.

I know to do these action for single record bt not for multiple. I have taken check box as array[] where it will store the primary keys of the selected records. I do not Know to use them in a professional manner.

Also note that I need to perform either of the two actions on single table. Please help me to do so.

<?php

$sql="SELECT * FROM transaction WHERE status='$selstatus'AND merchant_id='$selmerchantid' ORDER BY transaction_date AND transaction_date BETWEEN '$from' AND '$to' " ;

$result = mysql_query($sql) or die(mysql_error());  ;

$result = mysql_query($sql) or die(mysql_error());

// Print the column names as the headers of a table

echo '<table class="tableviewsales"><tr>';

for($i = 0; $i < mysql_num_fields($result); $i++) {

    $field_info = mysql_fetch_field($result, $i);

    echo "<th>{$field_info->name}</th>";

}

// Print the data

while($row = mysql_fetch_row($result)) {

    echo "<tr>";

    foreach($row as $_column) {

        echo "<td>{$_column}</td>";

    }

          $transactionid = $row[0];

          echo '<td> <input name="action[]" type="checkbox"  value="'. $transactionid.'">' ;

    echo "</tr>";

}

echo "</table>";

?>

</div>

<div id="action">

<table>

<tr>

<td> <input type="submit" value="Change Status" class="btn">

<input type="hidden" name="MM_update" value="changestatus" /> </td>

<td> <input type="submit" value="Send Report" class="btn">

<input type="hidden" name="MM_update" value="sendreport" /> </td>

</tr>

</table>

</div>