SELECT paper_id ,symptom_name FROM My_table
WHERE (symptom_name= "" AND symptom_name= "")

SELECT paper_id ,symptom_name FROM My_table
WHERE symptom_name IN ("symptom1", "symptom2", "symptom3", "symptom4")

paper_symptom_id  paper_id  symptom_id
(autogenerated)   1         6
(autogenerated)   1         7

select s.*
from papers p
inner join paper_symptoms ps
on ps.paper_id = p.paper_id
inner join symptoms s
on s.symptom_id = ps.symptom_id
where p.paper_id = 1