Extbase - get created sql from query

In TYPO3 6.2 you can use Extbase DebuggerUtility to debug the query.

Add this code before $query->execute():

/** @var Typo3DbQueryParser $queryParser */
$queryParser = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance('TYPO3\\CMS\\Extbase\\Persistence\\Generic\\Storage\\Typo3DbQueryParser');
\TYPO3\CMS\Extbase\Utility\DebuggerUtility::var_dump($queryParser->parseQuery($query));

Check this snippet, although it's not very comfortable in use it helps a lot:

in general you need this code at the end of the buildQuery(array $sql) method (*) - right before return $statement;

if (in_array("your_table_name", $sql['tables'])) {
    var_dump($statement);
    print_r($statement);
}

(*) Class file:

• TYPO3 ver.: 4.x: typo3/sysext/extbase/Classes/Persistence/Storage/Typo3DbBackend.php
• TYPO3 ver.: 6.x: typo3/sysext/extbase/Classes/Persistence/Generic/Storage/Typo3DbBackend.php

In 6.2.x ...

You can try within \TYPO3\CMS\Core\Database\DatabaseConnection::exec_SELECTquery method, just add the condition after fetching the $query, like (trim is important!):

public function exec_SELECTquery($select_fields, $from_table, $where_clause, $groupBy = '', $orderBy = '', $limit = '') {
    $query = $this->SELECTquery($select_fields, $from_table, $where_clause, $groupBy, $orderBy, $limit);

    if (trim($from_table) == 'fe_users') {
        DebuggerUtility::var_dump($query);
    }

// rest of method

An easy way without changing any Typo3 core code and not mentioned in any forum so far is using the php "serialize()" method:

$result = $query->execute();
echo (serialize($result));

In the result object you find the SQL query ("statement;" ...)