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SQL INNER JOIN 3+ tables


nadeemshafi9

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somone help please i left my book at home i cant rember how to do a INNER JOIN on more than 3 tables ??

 

here is my current join where i have put conditions in the WHERE istead of joining but this is prooviung to be slow.

 

"SELECT ".

"p.physreq_title, ".

"p.physreq_text, ".

"e.enviroserv_title, ".

"e.enviroserv_text, ".

"f.finish_title, ".

"f.finish_text ".

 

"FROM ".

"physreq_table p, ".

"enviroserv_table e, ".

"finish_table f, ".

"xref_physreq_rds x_p_r, ".

"xref_enviroserv_rds x_e_r, ".

"xref_finish_rds x_f_r, ".

"rds_table r ".

 

"WHERE ".

"p.physreq_id = x_p_r.physreq_id ".

"AND r.rds_id = x_p_r.rds_id ".

"AND e.enviroserv_id = x_e_r.enviroserv_id ".

"AND r.rds_id = x_e_r.rds_id ".

"AND f.finish_id = x_f_r.finish_id ".

"AND r.rds_id = x_f_r.rds_id ".

 

"AND r.rds_id = '".$this_rds->rds_id."';";

 

these are many to many relations so they have XREF tables inbetween

 

please help

 

thankls

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