Concatenating date and time fields - sql

Question

I have a table invoices with this fields:
invDate -> a date field
invTime -> a time field
I need to do querys like
SELECT top 10 * from invoices WHERE DATETIME(invDate+invTime)
BETWEEN DATETIME('2013-12-17 17:58') AND DATETIME()
or something like that. I don't know how to concatenate the invDate and invTime to create a datetime field. The only thing that i could do is this horribly thing:
DATETIME( YEAR(invDate), MONTH(invDate), DAY(invDate), 17, 52 ) AS MyDatetime
Couldn't even get hour and time with hour(invTime) and minute(invTime):
DATETIME( YEAR(invDate), MONTH(invDate), DAY(invDate),
HOUR(invTime), MINUTE(invTime) ) AS MyDatetime
I'm doing the querys throught the VFP Odbc Driver via PHP.

Answer 1

You were pretty close. If the value coming from PHP is not of a date/time, how could VFP interpret it properly. VFP also has a function CTOT() (character to time), and expects it in the format of 'yyyy-mm-ddThh:MM:ss??'
yyyy = 4 digit year
mm = 1 OR 2 digit month
dd = 1 OR 2 digit day
T -- literally the letter "T"
hh = 1 OR 2 digit hour (but typical is 2 anyhow)
MM = 1 or 2 digit minute (but typical is 2)
ss = 1 or 2 digit for seconds -- not required
?? = "AM" or "PM" if you wanted to explicitly provide that vs 24 hour clock
The MM and ss are optional, so if you finished with "T1" would be 1:00:00am
Now, to finish your query.
WHERE DATETIME(invDate+invTime)
BETWEEN DATETIME('2013-12-17 17:58') AND DATETIME()
Since this appears to be querying all invoices between a given date/time and NOW (via DateTime()), you don't even need between, you can do
WHERE YourTable.Column > CTOT( '2013-12-17T17:58')
If you specifically DID have a date/time range to consider, THEN you could do something like
WHERE YourTable.Column BETWEEN CTOT( '2013-12-05T10:00') AND CTOT( '2013-12-14T11:58')
PROBLEMS WITH your DATE() and TIME() implementations
The problem is Date() is a function to either return current date, or create based on y/m/d provided such as date( 2013, 12, 7 ). If you are passing a string, use CTOD( 'mm/dd/yyyy' ) such as CTOD( 12, 7, 2013 ).
As for the TIME() function that just expects a number and is of no use for you. From the OleDbProvider, your best bet is to just create a php function that builds a single string in the CTOT() format I've described and pass to the php function the date and time fields. Then use that as your "CTOT( functionReturnResult )"

Answer 2

To add a Date and a Time Field together you will need to convert them both to a same datatype 1st and than just simply add them together something like this....
DECLARE #D DATE = '2013-12-17'
DECLARE #T TIME = '17:58:00'
SELECT CAST(#D AS DATETIME) + CAST(#T AS DATETIME)
Result
2013-12-17 17:58:00.000
Your Query
SELECT top 10 *
from invoices
WHERE CAST(invDate AS DATETIME) + CAST(invTime AS DATETIME)
BETWEEN '20131217 17:58:00.000' AND GETDATE()