Where in the Bible does it says one shoudn't get drunk?

First, do you mean sober= not drunk, or sober= sensible, serious?

Just to start you off on both:

'Let us behave decently, as people who live in the light of day. No wild parties, drunkenness, sexual immorality, promiscuity, rivalry, or jealousy! Instead, clothe yourselves with the Lord Jesus Christ, and do not obey your flesh and its desires.'[Romans 13:13-14]

But as for you, teach what is consistent with healthy doctrine. Older men are to be sober, serious, sensible, and sound in faithfulness, love, and endurance. [Titus 2:1-2]

Note that I would strongly recommend reading around these passages (and any others) to get the context. Picking an odd verse at random to prove a point is somewhere between unhelpful and dangerous.