Print the error message returned from the SQL query

Question

I created a custom module where I am querying the database, for example with code similar to the following one.

$query = db_select('node', 'n');
$query->fields('n', array('nid'));
$nid = $query->execute()->fetchField();

I want to print the warning, error, and success messages after the execution of the query. How can I achieve this?

Answer 1

Try to follow below code..

   try {
        $query = db_select('node', 'n');
        $query->fields('n', array('nid'));
        $nid = $query->execute()->fetchField();
        drupal_set_message(t('Print your sucess message here'));
      }
    catch(Exception $e){
        drupal_set_message(t('Print your error message here'),'error');
    }

Answer 2

You can display drupal messages using the pre-defined function drupal_set_message().

For example:

$query = db_select('node', 'n');
$nid = $query->fields('n', array('nid'));
$nid = $nid->execute()->fetchField();
if(!empty($nid)){
     //Do something
     drupal_set_message(t('Your success message'), $type = 'status');
}else{
    //Do something
     drupal_set_message(t('Your error message'), $type = 'error');
}

For more information about messages, click here