Arrays should be indexable from the end too

[rmoff]

I want to be able to access the last element(s) in an array.

KSQL support accessing elements based on offset from the start:

ksql> SELECT SCHEDULE_SEGMENT_LOCATION[0] FROM SCHEDULE_01 LIMIT 1;
{"record_identity":"LO","engineering_allowance":"3","line":"AL","public_departure":"0506","tiploc_code":"YORK","departure":"0508","location_type":"LO","platform":"9"}
Limit Reached
Query terminated

But not the end:

ksql> SELECT SCHEDULE_SEGMENT_LOCATION[-1] FROM SCHEDULE_01 LIMIT 1;
null
Limit Reached
Query terminated