I want to retrieve data from 4 tables in SQL Server -

i want retrieve data 4 tables. patient table has id pk foreign key in other 3 tables ett, phar , ssc. patient lie in 1 category. i.e patient id pt1 exists in either of 3 tables. want retrieve patient info along associated category.

my query is:

select * patient p inner join ett t  on p.patient_id = t.patient_id  || inner join pharmacological ph  on p.patient_id = ph.patient_id 

i used or clause because want 1 inner join executing @ 1 time. not giving me results, suggestions??

....patient table has id pk foreign key in other 3 tables name: ett, phar , ssc a patient lie in 1 category. example, patient id pt1 exists in either of 3 tables.

based on statement, can join tables in table patient using left join since record can exist on 1 table. query below uses coalesce returns first non-null value int list.

the thing need manually specify column names want shown on list shown below.

select  a.*,         coalesce(t.cola, p.cola, s.cola) cola,          coalesce(t.colb, p.colb, s.colb) colb,         coalesce(t.coln, p.coln, s.coln) coln    patient         left join ett t             on a.patient_id = t.patient_id         left join phar p             on a.patient_id = p.patient_id         left join ssc s             on a.patient_id = s.patient_id 

to further gain more knowledge joins, kindly visit link below:

• visual representation of sql joins