I am working with db2v8.2.2 aix 5.2

is there any function I caculate different between to times.

Thank for your help

you mean this :
db2admin:/cygdrive/c/workdir: db2 "select * from tim"

COL1 COL2
-------- --------
08:40:37 05:40:37

1 record(s) selected.

db2admin:/cygdrive/c/workdir: db2 "select col1-col2 from tim"

1
--------
30000,

1 record(s) selected.

Thank you for your help, could you please tell me what is 30000, is it second?
but 3 hours difference can not be 30000 seconds?

30000
means
03 hours 00 minutes 00 seconds

Oh.... Thank you for your help.

you can also use the timestampdiff function wich can show the difference from 'Fractions of a second' up to 'Years'.

example: diff of one day in seconds
db2 => values timestampdiff(2,char((current timestamp + 1 day) - current timestamp ))

1
-----------
86400

1 record(s) selected.

regards,
I.