Question

I have a column DECIMAL(9,6) i.e. it supports values like 999,123456.

But when I insert data like 123,4567 it becomes 123,456700

How to remove those zeros?

Answer 1

A decimal(9,6) stores 6 digits on the right side of the comma. Whether to display trailing zeroes or not is a formatting decision, usually implemented on the client side.

But since SSMS formats float without trailing zeros, you can remove trailing zeroes by casting the decimal to a float:

select 
    cast(123.4567 as DECIMAL(9,6))
,   cast(cast(123.4567 as DECIMAL(9,6)) as float)

prints:

123.456700  123,4567

(My decimal separator is a comma, yet SSMS formats decimal with a dot. Apparently a known issue.)