I am learning German cases and accidentally I wrote below two sentences.
Is the first sentence correct?
Ich habe deines Tisches.(G)
Ich habe deinen Tisch.(Akk)
I am learning German cases and accidentally I wrote below two sentences.
Is the first sentence correct?
Ich habe deines Tisches.(G)
Ich habe deinen Tisch.(Akk)
No, your first sentence is wrong.
Verbs that rule the genitive exist in German, but they are somewhat rare and haben is not one of these verbs.
A non-exhaustive list with some examples would be
It is the verb that governs whether the object is in the accusative, dative, or genitive case.
In this event, "haben" puts the object in the accusative case.
A verb like "helfen" would put the object in the dative case.
Tofro also pointed out a handful of (abstract) verbs that put the object into the genitive case. "Haben" is not one of them.
You may have been confused because there is a "possessive" involved in the sentence. But the modifier, "mein," fulfills this function adequately without the need for using the genitive case to create the possessive. Only when the possessive applies to the verb, e.g annehmen, do you use the genitive case; not when it pertains to the noun, Tisch.
Haben + Akk Haben geht immer mit Akkusative in der Bedeutung von "To have something". Das Wort "dein" beschreibt schon das Eigentumsverhältnis.