src/Driver/Compiler.php
protected function compileGrouping(array $grouping): string
    {
        $statement = '';
        foreach ($grouping as $identifier) {
            $statement .= $this->quote($identifier);
        }

        return $statement;
    }
protected function compileGrouping(array $grouping): string
    {
        $statement = '';
        foreach ($grouping as $identifier) {
            $statement .= $this->quote($identifier);
        }

        return $statement;
    }
protected function compileGrouping ( array $ grouping ) : string { $ statement = '' ; foreach ( $ grouping as $ identifier ) { $ statement .= $ this -> quote ( $ identifier ) ; } return $ statement ; }
Compiler GROUP BY statement.

@param array $grouping

@return string
Compiler GROUP BY statement .