JOIN condition v.s. WHERE condition

[Ran]

Hi all,
If my post is irrelevant to the list, please let me know.
I have conditions (REGEXP 'STRING' or ='STRING')  as JOIN condition or as
WHERE clause condition, i wonder for a 10 table LEFT/INNER JOIN query, which
approach is better and why.

Thanks,
ran

i.e.
               "    SELECT                                    "+
               "      m.id_company,                            "+
               "      m.name,                                "+
               "      m.division,                            "+
               "      m.is_deleted,                            "+
               "      GROUP_CONCAT( DISTINCT
pt.name,':\t',p.valueSEPARATOR '\n') AS phone_concat "+
               "    FROM                                    "+
               "      crm_company m                            "+
               "      INNER JOIN                            "+
               "        crm_company m1                        "+
               "        ON                                     "+
               "            m1.id_company = m.id_company    "+
               "            AND                                "+
               "              (m.name REGEXP '^"+q+"| "+q+"'
"+
               "                  OR m.division REGEXP '^"+q+"| "+q+"')
"+
               "    LEFT JOIN     "+
               "        crm_communication_company_link pmk        "+
               "        ON pmk.id_company = m.id_company "+
               "    LEFT JOIN                                    "+
               "        crm_communication p ON pmk.id_communication =
p.id_communication "+
               "    LEFT JOIN     "+
               "        crm_communication_type pt ON
p.id_communication_type = pt.id_communication_type "+
               "    LEFT JOIN                                    "+
               "        crm_customer_company_link cmk            "+
               "        ON cmk.id_company = m.id_company        "+
               "     LEFT JOIN                                    "+
               "        crm_has_contact hc                        "+
               "        ON hc.cid = cmk.id_customer                "+
                   _GROUP_CTRL    +
               "    WHERE    "+
               "        m.is_deleted = 0    "+
               "    GROUP BY                                "+
               "      m.id_company                            "+
               "    ORDER BY                                "+
               "      m.name REGEXP '^"+q+"' DESC,             "+
               "      m.name ASC                             ";

Compare to that moved to WHERE clause:

               "    SELECT                                    "+
               "      m.id_company,                            "+
               "      m.name,                                "+
               "      m.division,                            "+
               "      m.is_deleted,                            "+
               "      GROUP_CONCAT( DISTINCT
pt.name,':\t',p.valueSEPARATOR '\n') AS phone_concat "+
               "    FROM                                    "+
               "      crm_company m                            "+
              # self inner join removed
               "    LEFT JOIN     "+
               "        crm_communication_company_link pmk        "+
               "        ON pmk.id_company = m.id_company "+
               "    LEFT JOIN                                    "+
               "        crm_communication p ON pmk.id_communication =
p.id_communication "+
               "    LEFT JOIN     "+
               "        crm_communication_type pt ON
p.id_communication_type = pt.id_communication_type "+
               "    LEFT JOIN                                    "+
               "        crm_customer_company_link cmk            "+
               "        ON cmk.id_company = m.id_company        "+
               "     LEFT JOIN                                    "+
               "        crm_has_contact hc                        "+
               "        ON hc.cid = cmk.id_customer                "+
                   _GROUP_CTRL    +
               "    WHERE    "+
               "        m.is_deleted = 0    AND ("+
               "            AND                                "+
               "              (m.name REGEXP '^"+q+"| "+q+"'
"+
               "                  OR m.division REGEXP '^"+q+"| "+q+"')  )
"+
               "    GROUP BY                                "+
               "      m.id_company                            "+
               "    ORDER BY                                "+
               "      m.name REGEXP '^"+q+"' DESC,             "+
               "      m.name ASC                             ";