does not work, who can help?
{{$node[“HTTP Request - Voucher”].json[“useCollectiveContact”] ? "false: " + $node[“NX - sucht Kontakt”].json[“id”] : ‘542’}}
Hi @Micha00, welcome to the community 
Unfortunately, it seems you omitted a lot of information from the forum template when posting. Perhaps you can provide an example workflow using which other forum users can reproduce your problem and confirm which version of n8n you are currently running?
In general, the ternary operator works inside an expression used in a Set node, check out this example: