How to make SUMIF not default to 0 but to blank in Google Sheets?

My goal is to sum values in a row if they are present and leave the cell empty it there are no values. I used a formula: =SUMIF(A1:C1; "<>"; A1:C1) – but Google Sheets inserts a default value 0 – I don’t want the default value.

Example:
A, B, C colums are number values. D is the sum column.

This is how my formula works:

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This is how I want it to work:

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