SELECT toYYYYMM(toDate('2017-07-21'));
SELECT toYYYYMMDD(toDate('2017-07-21'));
SELECT toYYYYMMDDhhmmss(toDate('2017-07-21'));
SELECT toYYYYMM(toDateTime('2017-07-21T11:22:33'));
SELECT toYYYYMMDD(toDateTime('2017-07-21T11:22:33'));
SELECT toYYYYMMDDhhmmss(toDateTime('2017-07-21T11:22:33'));