This is an interesting question Gavril . The conjugation of Danish verbs doesn´t include specific subjunctive or conditional verbal forms or moods, in other words there are no specific subjunctive verbal forms recognizable as such out of context. A subjunctive or conditional construction is therefore created by using the available verbal forms in a different tense (referred to as “verbalomskrivning”). This typically, although not exclusively, is done by using the past tense or the infinitive… very much comparable to what we see in modern English.
-As such there is the hypothetical scenario:
Hvis det skulle regne i morgen, vil udflugten være aflyst (the subjunctive: If it were to rain tomorrrow...)
Hvis det regner i morgen, er udflugten aflyst (the indicative: If it rains tomorrow…)
I would use number one if I feel it is very unlikely that it will rain. I checked the weather forecast and they predict sunshine all day tomorrow, but if it were to rain (nevertheless)…
I would use number two if I feel there´s a possibility that it may rain. It´s been raining all week and if it rains (again) tomorrow…
Hvis jeg var dig....(the subjuntive: If I were you)
Kunne det tænkes, at han var morderen (the subjuntive: might it be possible that...)
-To express wishes, hopes:
Long live the Queen, the centenarian etc.Længe leve dronningen, den hundredårige osv.
In religious contexts e.g. The Lord´s Prayer: Helliget vorde/være/blive dit navn, komme dit rige (Hallowed be Thy Name, Thy Kingdom come), Herren være med jer (The Lord be with you).