count different values in column?

Hello,
today I have a new question :)

I've a resulttable is generated by a couple of subselects and joins which
contains only one column.

Now I want to count the different values in the column.

Resulttable :  a
------
10
12
12
12
14
14
15

I need the value which is repeated most in the resulttable (in this example
12 ) !


Any suggestions ?


Thx
berger