I have the following in my table:

create table example (

     col_a int4,
     col_b int4,
     average_col = numeric


)

col_a = 309
col_b = 16

309 / 16 = 19.3125

When I do the following, I only get 19. Not (19.0, or 19.3125, 19.3):

TRUNC((col_a/col_b),1) = 19

What am I doing wrong?