MySQL SELECT from multiple columns from tables

Question

I am trying to retrieve information from a mysql database. I have the following tables:

Qualifications(qualificationid, qualificationname, personid,status)

Address(addressid, addressline1,city,province,areacode,personid)

score(scoreid, score.choices,personid,jobid)

I use typed the following mysql statement to retrieve the data

SELECT score.personid, qualifications.qualificationname, score.score
FROM
Qualifications, Score, Address
WHERE
score.jobid=58
AND
qualifications.qualificationName ='Human Resource Management'
AND
aadress.province ='Western Cape'
ORDER BY score.score
LIMIT 0,20;

this seems to work for everything else but doesn't restrict the province to western cape.

Answer 1

Why don't you use joins? Like so:

SELECT s.personid, q.qualificationname, s.score
  FROM Score s
  INNER JOIN Qualifications q ON q.personid = s.personid AND q.qualificationName ='Human Resource Management'
  INNER JOIN Address a ON a.personid = s.personid AND a.province ='Western Cape'
  WHERE s.jobid = 58
  ORDER BY s.score DESC
  LIMIT 0,20;

Answer 2

You will need to define relations. The system now has no clue how Addresses relate to Scores or Qualifications in your example. By adding a GROUP BY score.personid and AND score.personid = address.personid and score.personid = qualifications.personid you might fix your problems.

Also, using JOINS is probably more efficient as it does basically the same.