let roomLength = 0
let studentLength = 0
    db.query("SELECT * FROM rooms", (err, result)=>{
    if(err){
        console.log(err);
    }else{
        roomLength = result.length
    }
})

db.query("SELECT * FROM student", (err, result)=>{
    if(err){
        console.log(err);
    }else{
       studentLength = result.length
    }
})

console.log(roomLength, studentLength)

The studentLength and roomLength is showinh as 0 0 when logging it outside of the db.query function. But its working fine when adding console.log inside db.query