function test_get_table_alias()
 {
     $parser = new SQL_Parser();
     $compiler = new SQL_Compiler();
     $sql = 'select foo, bar from Table1';
     $parsed = $parser->parse($sql);
     $wrapper = new SQL_Parser_wrapper($parsed);
     $wrapper->addColumn('testColumn', 'a');
     $this->assertEquals('Table1', $wrapper->getTableAlias('Table1'));
     $err = $wrapper->getTableAlias('TableNonExistent');
     $this->assertTrue(is_a($err, 'PEAR_Error'));
     $sql = 'select a.foo, b.bar from Table1 as a inner join Table2 as b on a.foo=b.bar';
     $parsed = $parser->parse($sql);
     //print_r($parsed);
     $wrapper = new SQL_Parser_wrapper($parsed);
     $this->assertEquals('a', $wrapper->getTableAlias('Table1'));
     $this->assertEquals('b', $wrapper->getTableAlias('Table2'));
 }