Neither here nor there: 
毫不相干, 不重要

Example: Even though we talked a lot about our tastes in food, it was neither here nor there as we had to cater to our guest’s tastes
例如:   虽然我们谈了很多关于我们的食物口味，但这都毫不相干，因为我们不得不迎合我们客人的口味。