@Test
  public void testUnionAll() throws ParseException {
    parse("select * from (select * from `c/b/o_t1` order by key, c_boolean, value, dt)a union all select * from (select * from `//cbo_t2` order by key, c_boolean, value, dt)b");
    parse("select key from (select key, c_int from (select * from `c/b/o_t1` union all select * from `//cbo_t2` where `//cbo_t2`.key >=0)r1 union all select key, c_int from `cbo_/t3////`)r2 where key >=0 order by key");
    parse("select r2.key from (select key, c_int from (select key, c_int from `c/b/o_t1` union all select key, c_int from `cbo_/t3////` )r1 union all select key, c_int from `cbo_/t3////`)r2 join   (select key, c_int from (select * from `c/b/o_t1` union all select * from `//cbo_t2` where `//cbo_t2`.key >=0)r1 union all select key, c_int from `cbo_/t3////`)r3 on r2.key=r3.key where r3.key >=0 order by r2.key");
  }
Parser tests special character in table names.
parser/src/test/org/apache/hadoop/hive/ql/parse/TestSpecialCharacterInTableNames.java