I'm having the value date and time variable but i want dateandtime in one variable?

[MSK4]

data have;

a='10jan2012'd;

b='10:20:30't;

format a date9. b time8.;

run;

but i want output like this 10jan2012:10:20:30

how can i add two values?

Thanks in advance.

[MSK4]

I have tried this but i donna whether it right or wrong.
please correct me .
data a;
a='10dec2019'd;
b='10:12:30't;
format a date9. b time8.;
run;
data ab;
set a;
c=put(a,date9.);
d=put(b,time8.);
g=input(catx(':',put(a,date9.),put(b,time8.)),datetime20.);
format g datetime20.;
run;

[andreas_lds]

try

datetime = dhms(a, hour(b), minutes(b), seconds(b));

[Ksharp · Accepted solution]

data have;
a='10jan2012'd;
b='10:20:30't;
want=dhms(a,0,0,b);
format a date9. b time8. want datetime20.;

run;