Eliminate space between fields in a mail merge document if a field is blank

I am doing a mail-merge document with fields similar to this:

<Field 1> <Field 2>

There is a space between the two fields and what I would like to do is eliminate the space if <Field 2> is empty.

Any assistance would be appreciated.

What kind is the underlying database filling the mail merge fields?

It’s a Calc spreadsheet.

In this case, I would nail down the problem with a Calc formula, merging <Field 1> and <Field 2> in the right ways.

Don’t know of this will work in LO but in gLabels (a Linux application for generating labels and business cards) in the template you place a $ character at the beginning of each line and between fields where you wish to suppress a filed that contains no value.
Maybe worth a punt since many applications follow similar arrangements?

No it doesn’t.

Thanks for the info Villeroy. Done and it works well.

Depending on your situation (if you need to remove just interim space, or the whole line), you may use either Hidden text, or Hidden Paragraph fields, with a condition when both the fields are empty.