Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE Dorm ( dormid INTEGER, dorm_name VARCHAR(20), student_capacity INTEGER, gender VARCHAR(1) )
TABLE: CREATE TABLE Student ( StuID INTEGER, LName VARCHAR(12), Fname VARCHAR(12), Age INTEGER, Sex VARCHAR(1), Major INTEGER, Advisor INTEGER, city_code VARCHAR(3) )
TABLE: CREATE TABLE Has_amenity ( dormid INTEGER, amenid INTEGER )
TABLE: CREATE TABLE Lives_in ( stuid INTEGER, dormid INTEGER, room_number INTEGER )
TABLE: CREATE TABLE Dorm_amenity ( amenid INTEGER, amenity_name VARCHAR(25) )

### Question ###
Give me a histogram for how many students are older than 20 in each dorm?

### Accurate SQL ###

SELECT dorm_name, COUNT(*) FROM Student AS T1 JOIN Lives_in AS T2 ON T1.stuid = T2.stuid JOIN Dorm AS T3 ON T3.dormid = T2.dormid WHERE T1.Age > 20 GROUP BY T3.dorm_name