You can test the field for being not empty, or being empty, and just change around where the field is set.
if(!isempty([Release Type 2], 0), [Release Type 2],,)
OR
if(isempty([Release Type 2], 0),, [Release Type 2])
https://wiki.jriver.com/index.php/Conditional_Functions#If.28.E2.80.A6.29https://wiki.jriver.com/index.php/Test_and_Comparison_Functions#IsEmpty.28.E2.80.A6.29You can also use the ifelse function to simplify a bit.
ifelse(!isempty([Release Type 2], 0), [Release Type 2])
and
ifelse(!isempty([Release Type 3], 0), [Release Type 3])
https://wiki.jriver.com/index.php/Conditional_Functions#IfElse.28.E2.80.A6.29As you want to include brackets in the output, you also need to "escape" each bracket around the Release Types you are adding, using the escape character "/" so that MC doesn't treat them as part of the expression;
/( and /)
But then you don't want the brackets showing if neither Release Type 2 or 3 have content.
ifelse(!isempty([Release Type 2][Release Type 3], 0), /()
Will yield an opening bracket "(" if either [Release Type 2] or [Release Type 3] contain any value.
Similar expression section for the closing bracket.
ifelse(!isempty([Release Type 2][Release Type 3], 0), /))
So the full expression using the ifelse command would be;
[Album] ifelse(!isempty([Release Type 2][Release Type 3], 0), /()ifelse(!isempty([Release Type 2], 0), [Release Type 2]) ifelse(!isempty([Release Type 3], 0), [Release Type 3])ifelse(!isempty([Release Type 2][Release Type 3], 0), /))
Or in indented form;
[Album]
ifelse(
!isempty(
[Release Type 2][Release Type 3], 0
), /(
)
ifelse(
!isempty(
[Release Type 2], 0
), [Release Type 2]
)
ifelse(
!isempty(
[Release Type 3], 0
), [Release Type 3]
)
ifelse(
!isempty(
[Release Type 2][Release Type 3], 0
), /)
)