The hardest part of the question was figuring out what is the result of 5/3.1

IMHO the point of the question would make more sense if it had been changed to 5/3.0 as the result of the function would actually be affected by the third parameter of the ROUND function unlike in this question.

To illustrate:

select

Example = 'Your example'

,input_data = '5/3.1'

,Truncation = ROUND(1.612903, 1, 1) -- 1.600000

,Rounding = ROUND(1.612903, 1, 0) -- 1.600000

union all

select

'Better example'

,'5/3.0'

,ROUND(1.666666,1,1) -- 1.600000

,ROUND(1.666666,1,0) -- 1.700000

Example input_data Truncation Rounding

-------------- ---------- ------------ ----------

Your example 5/3.1 1.600000 1.600000

Better example 5/3.0 1.600000 1.700000

Regards,

Hrvoje Piasevoli