Question

I have a 3 fields.

1. Date (as DATE)
2. Time (as TIME)
3. GMT Offset (as TIME)

I need to add the 3 fields together to retrieve a final DATETIME field in which to work with.

i) How do I do that and cope with overlapping days when the GMT offset carries the date into a new day?

ii) Is it more efficient to store the Date and Time as a single DATETIME field? And if so, what about the GMT offset? Keep it as a TIME field, or perhaps something else?

Answer 1

My opinion is that it is better to store the first two fields as a DATATIME (MyDateTime) field. Then, it’s a matter of using

SELECT TIMESTAMPADD(HOUR,GMT_Offset,MyDateTime) to put it together.

Of course, if you want, you could just throw it all of them into a single expression:

SELECT TIMESTAMPADD(HOUR,GMT_Offset,TIMESTAMP(MyDate,MyTime))

I am assuming that MyDate and MyTime are already in GMT.