@Test public void testNotEqualsOperatorIntervals() {
    tester.checkBoolean(
        "interval '2' day <> interval '1' day",
        Boolean.TRUE);
    tester.checkBoolean(
        "interval '2' day <> interval '2' day",
        Boolean.FALSE);
    tester.checkBoolean(
        "interval '2:2:2' hour to second <> interval '2' hour",
        Boolean.TRUE);
    tester.checkNull(
        "cast(null as interval hour) <> interval '2' minute");

    // "!=" is not an acceptable alternative to "<>"
    tester.checkFails(
        "1 ^!^= 1",
        "(?s).*Encountered: \"!\" \\(33\\).*",
        false);
  }

  @Test public void testBangEqualIsBad() {
    // Quoth www.ocelot.ca:
    //   "Other relators besides '=' are what you'd expect if
    //   you've used any programming language: > and >= and < and <=. The
    //   only potential point of confusion is that the operator for 'not
    //   equals' is <> as in BASIC. There are many texts which will tell
    //   you that != is SQL's not-equals operator; those texts are false;
    //   it's one of those unstampoutable urban myths."
    checkFails("'abc'^!^=123",
        "Lexical error at line 1, column 6\\.  Encountered: \"!\" \\(33\\), after : \"\"");
  }