Drupal - Print the query which is built using db_select()

SelectQuery implements SelectQuery::__toString(), which is called in the contexts where a string is required.

Consider the following code.

global $theme_key;

$query = db_select('block')
  ->condition('theme', $theme_key)
  ->condition('status', 1)
  ->fields('block');

print $query;

Its output is the following one.

SELECT block.*
FROM 
{block} block
WHERE  (theme = :db_condition_placeholder_0) AND (status = :db_condition_placeholder_1)

To get the array of arguments used for the query, you can call SelectQuery::arguments().

The following code prints the query and its arguments using the functions made available from the Devel module.

global $theme_key;

$query = db_select('block')
  ->condition('theme', $theme_key)
  ->condition('status', 1)
  ->fields('block');

dpm((string) $query);
dpm($query->arguments());

The Devel module is not necessary, though, and you could drupal_set_message() to show the output. For example, you could use the following function to get a string with the placeholders replaced by their actual values.

function _get_query_string(SelectQueryInterface $query) {
  $string = (string) $query;
  $arguments = $query->arguments();

  if (!empty($arguments) && is_array($arguments)) {
    foreach ($arguments as $placeholder => &$value) {
      if (is_string($value)) {
        $value = "'$value'";
      }
    }

    $string = strtr($string, $arguments);
  }

  return $string;
}

The previous example code I shown would become the following one.

global $theme_key;

$query = db_select('block')
  ->condition('theme', $theme_key)
  ->condition('status', 1)
  ->fields('block');

drupal_set_message(format_string('Query: %query', array('%query' => _get_query_string($query))));

function _get_query_string(SelectQueryInterface $query) {
  $string = (string) $query;
  $arguments = $query->arguments();

  if (!empty($arguments) && is_array($arguments)) {
    foreach ($arguments as $placeholder => &$value) {
      if (is_string($value)) {
        $value = "'$value'";
      }
    }

    $string = strtr($string, $arguments);
  }

  return $string;
}

Notice that SelectQuery::arguments() returns the array of query arguments only when it is called after SelectQuery::__toString(), SelectQuery::compile(), or SelectQuery::execute(); otherwise, SelectQuery::arguments() returns NULL.

You could use a function similar to the following one to get the string query, with the placeholders replaced with the arguments.

You can use dpq() to display the query, and dpr() to display the result.

  $query = db_select('users','u');
  $query->fields('u');
  $query->condition('u.uid', 1042);
  $result = $query->execute()->fetchAll();

  dpq($query); // Display the query. 
  dpr($result); // Display the query result.

Another option is:

global $theme_key;

$query = db_select('block')
  ->condition('theme', $theme_key)
  ->condition('status', 1)
  ->fields('block');

print strtr((string) $query, $query->arguments());