Use the I option to suppress the output of symbols that still contain their initial values.
&symbol(I)&
Assuming KNA1-UMSAT contains the value 0 and the currency is EUR.
&KNA1-UMSAT& -> 0.00
&KNA1-UMSAT(I)& ->
If the field contains an amount other than 0, this value is printed in the normal way.
&KNA1-UMSAT& -> 700.00
&KNA1-UMSAT(I)& -> 700.00