JOIN or WHERE?

Okay .. I don’t really expect any response from the regular readers today. This is another technical post.

I’m just wondering which is more efficient.

SELECT
  documents.*,
  companies.code AS company_code,
  companies.name AS company_name,
  projects.code AS project_code,
  projects.name AS project_name,
  contacts.firstname AS contact_firstname,
  contacts.id AS contact_id
FROM
  documents
INNER JOIN
  (companies, projects, contacts)
ON
  (documents.company_id = companies.id
    AND documents.project_id = projects.id
    AND contacts.company_id = companies.id)
WHERE
  (documents.document_type = 'QUO'
    OR documents.document_type = 'QTS')
  AND documents.sub_type = 'QP'
ORDER BY documents.document_code DESC;

or …

SELECT
  documents.*,
  companies.code AS company_code,
  companies.name AS company_name,
  projects.code AS project_code,
  projects.name AS project_name,
  contacts.firstname AS contact_firstname,
  contacts.id AS contact_id
FROM
  documents, companies, projects, contacts
WHERE
  companies.id = documents.company_id
  AND projects.id = documents.project_id
  AND projects.contact_id = contacts.id
  AND (documents.document_type = 'QUO'
    OR documents.document_type = 'QTS')
  AND documents.sub_type = 'QP'
ORDER BY documents.document_code DESC;

Or maybe they’re exactly the same. Hmmm ..?