Help with complex query

Hello everyone, I have the following table in which I have a costumer name, transaction date y transaction time (two rows by

customer):

Customer Trans_date Trans_time
CUSTOMERA 2011-02-12 16:48:30
CUSTOMERA 2011-02-12 16:48:36
CUSTOMERB 2011-01-29 08:51:54
CUSTOMERB 2011-01-29 08:56:31
CUSTOMERA 2011-02-14 16:48:30
CUSTOMERA 2011-02-14 16:48:36

I need to group the records by customer name:

Customer Trans_date Trans_sTime Trans_fTime Elapsed_Time
CUSTOMERA 2011-02-12 16:48:30 16:48:36 X
CUSTOMERB 2011-01-29 08:51:54 08:56:31 X
CUSTOMERA 2011-02-14 16:48:30 16:48:36 X

But, it can be a situation in which a customer does not present the second read (unpaired record?)

Does anyone faced a similar problem?

pseudo tsql for the given data
SELECT customer, trans_date, 'stime'=min(trans_time), 'ftime'=max(trans_time), 'elapsed'=datediff(s,min(trans_time),max(trans_time))
FROM t
GROUP BY customer, trans_date
Dealing with datetime partition/boundary/npair -> yep, it's more complex (CTE is not optimal but ranking may be useful for a small dataset)