MySQL IF Condition in Where Section

Question

Is it possible to solve the IF condition, where is the Where clause that I want to select.

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IF(DATE_FORMAT(DATE(akDate), '%a')='SAT', USE WHERECLAUSE1, USE WHERECLAUSE2) 

Anyone got a snippet or something for me?

Thanks at Advance Jings

Answer 1

In this case, you can still write using a fairly common WHERE statement, such as:

 ... WHERE ( (DATE_FORMAT(DATE(akDate), '%a') = 'SAT') AND (WHERECLAUSE1) ) OR ( (DATE_FORMAT(DATE(akDate), '%a') != 'SAT') AND (WHERECLAUSE2) ) 

where, of course, you should replace WHERECLAUSE1 and WHERECLAUSE2 with the appropriate conditions.

Answer 2

Easy, you should read Boolean algebra . In your case, here we go:

 A = WhereClause1 B = WhereClause2 X = Choice 

You need to select lines with X && A OR lines with !X && B So basically your expression will be: (X && A) || (!X && B) (X && A) || (!X && B) . This leads to:

 ( (Choice AND WhereClause1) OR ((NOT Choice) AND WhereClause2) ) 

Answer 3

 $query = " SELECT apt.apt_id,apt.reg_id,apt.u_id,apt.b_id,apt.apt_bathroom,apt.apt_size,apt.apt_rent,apt.apt_desc,apt.negotiable,apt.apt_status,apt.govt_program,building.b_borough,building.b_zipcode,building.b_type,building.b_intersection,building.b_intersection2,building.b_desc FROM apt LEFT JOIN building ON apt.b_id = building.b_id WHERE apt.apt_status = 1 AND "; if ($search_size != 'empty') { $query .= "apt.apt_size = '".$search_size."' "; if ($search_borough != 'empty' || $search_zipcode != 'empty' ) { $query .= " AND "; } } if ($search_borough != 'empty') { $query .= "building.b_borough= '".$search_borough."' "; if ($search_zipcode != 'empty') { $query .= " AND "; } } if ($search_zipcode != 'empty') { $query .= "building.b_zipcode = '".$search_zipcode."' "; } $query .= "ORDER BY apt.apt_id DESC LIMIT $start,$perpage "; $query_run = mysql_query ($query); if (!$query_run) { echo 'Error In the Query limit.'; }