sqliteCreateFunction example

    catch (\PDOException $e) {
      if ($e->getCode() == static::DATABASE_NOT_FOUND) {
        throw new DatabaseNotFoundException($e->getMessage(), $e->getCode(), $e);
      }
      // SQLite doesn't have a distinct error code for access denied, so don't       // deal with that case.       throw $e;
    }

    // Create functions needed by SQLite.     $pdo->sqliteCreateFunction('if', [__CLASS__, 'sqlFunctionIf']);
    $pdo->sqliteCreateFunction('greatest', [__CLASS__, 'sqlFunctionGreatest']);
    $pdo->sqliteCreateFunction('least', [__CLASS__, 'sqlFunctionLeast']);
    $pdo->sqliteCreateFunction('pow', 'pow', 2);
    $pdo->sqliteCreateFunction('exp', 'exp', 1);
    $pdo->sqliteCreateFunction('length', 'strlen', 1);
    $pdo->sqliteCreateFunction('md5', 'md5', 1);
    $pdo->sqliteCreateFunction('concat', [__CLASS__, 'sqlFunctionConcat']);
    $pdo->sqliteCreateFunction('concat_ws', [__CLASS__, 'sqlFunctionConcatWs']);
    $pdo->sqliteCreateFunction('substring', [__CLASS__, 'sqlFunctionSubstring'], 3);
    $pdo->sqliteCreateFunction('substring_index', [__CLASS__, 'sqlFunctionSubstringIndex'], 3);
    $pdo->sqliteCreateFunction('rand', [__CLASS__, 'sqlFunctionRand']);