mysql - How to write a query that joins 3 tables -

i having issues query utilizes 3 different tables. believe using key words not exists , not within not positive on this. post query definition, tables using, , have tried far. in advance!

query:

find users create jobs utilize proteins. 

tables:

create table protein(pid integer,name varchar(50),primary key(pid));  create table job(uid integer,job_id integer auto_increment,input  varchar(500),status varchar(100),start_time time,finish_time time,foreign  key(uid) references user(uid) on delete cascade,primary key(job_id));  create table user(uid integer auto_increment,address varchar(40),city  varchar(20),state varchar(20),zipcode varchar(10), username  varchar(10),email varchar(30),primary key (uid));  create table job_protein(job_id integer, pid integer, primary key(job_id, pid)); 

what ive tried far...

select u.uid, j.jobid, count(j.jobid) job j inner join job_proteins p on j.jobid = p.jobid inner join user u on p.uid = u.uid group j.jobid having count(j.jobid) = (select count(pid) protein); 

does have jobs utilize every protein?.

missing member in group clause:

select u.uid, j.jobid, count(j.jobid) job j inner join job_proteins p on j.jobid = p.jobid inner join user u on p.uid = j.uid -- , had wrong alias here group u.uid, j.jobid -- right here having count(j.jobid) = (select count(pid) protein);