Something

// hmmm ... this statement to find matches between teachers and schools based on criteria such as location, 
// arrival, status and whether that match had been perviously made and stored in the sent_match table.
// any matches sent between school and teacher would get stored in sent match. 
// Syntaxically, can this statement be used to find matches that HAVEN'T appeared already in the sent_match table?
// I'm thinking the right/left joins make this impossible ..

SELECT teachers.name, teachers.arrival AS teachers_arrival,                                                             
                              teachers.location, school_jobs.school_jobs_id,                                                                   
                              sent_match.job_id, school_jobs.school,                                                                           
                              school_jobs.city, school_jobs.arrival AS school_jobs_arrival,                                                    
                              teachers.teacher_id, teachers.status, school_jobs.status                                                         
                                  FROM school_jobs                                                                               
                                  LEFT JOIN sent_match ON school_jobs.school_jobs_id = sent_match.job_id                         
                                  RIGHT JOIN teachers ON sent_match.teacher_id = teachers.teacher_id                             
                                  WHERE teachers.arrival BETWEEN school_jobs.arrival -2                                          
                                      AND school_jobs.arrival +2                                                                     
                                      AND ( teachers.location = school_jobs.city OR teachers.location = '1' )           
                                      AND teachers.status != -1                                                                      
                                      AND school_jobs.status != -1                                                                   
                                      AND ( teachers.teacher_id != sent_match.teacher_id                                             
                                      OR sent_match.teacher_id IS NULL)                                                              
                                      AND (school_jobs.school_jobs_id != sent_match.job_id                                           
                                      OR sent_match.job_id IS NULL)