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explode array in mysql

Posted on 2009-04-12
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Last Modified: 2013-12-12
i have a select query where i'm trying to get all records assigned to a person. is it possible to use explode within the query so that i only have to run 1 query?

the w.assignto is the field that may can contain multiple values.

1,2,3,4
$strsql = "SELECT m.id, DATE_FORMAT(m.mdate,'%m/%d/%Y'), m.item, m.description, m.status, w.assignto, s.sid, s.serviceby FROM maint m left join workassign w on m.id=w.mid left join service s on w.assignto=s.sid WHERE s.username='$loginuser' AND
w.assignto=s.sid";
 $result = mysql_query($strsql) or die("Cannot perform query: ".mysql_error());

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Question by:wakk0
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6 Comments
 
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Expert Comment

by:Roger Baklund
ID: 24125164
Try this:
$strsql = "SELECT ... AND s.sid in (w.assignto)";

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Expert Comment

by:NerdsOfTech
ID: 24126984
Translating cxr's response to this:
$strsql = "SELECT m.id, DATE_FORMAT(m.mdate,'%m/%d/%Y'), m.item, m.description, m.status, w.assignto, s.sid, s.serviceby FROM maint m left join workassign w on m.id=w.mid left join service s on w.assignto=s.sid WHERE s.username='$loginuser' AND
s.sid in (w.assignto";
 
 $result = mysql_query($strsql) or die("Cannot perform query: ".mysql_error());

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LVL 19

Expert Comment

by:NerdsOfTech
ID: 24126986
Corrected myself.
$strsql = "SELECT m.id, DATE_FORMAT(m.mdate,'%m/%d/%Y'), m.item, m.description, m.status, w.assignto, s.sid, s.serviceby FROM maint m left join workassign w on m.id=w.mid left join service s on w.assignto=s.sid WHERE s.username='$loginuser' AND
s.sid in (w.assignto)";
 
$result = mysql_query($strsql) or die("Cannot perform query: ".mysql_error());

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Author Comment

by:wakk0
ID: 24128131
that's not working....i know there are records assign to that person because i assign before i test and it still returns 0 records.
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Accepted Solution

by:
NerdsOfTech earned 125 total points
ID: 24128283
Unfortunately because the w.assignto is a comma demlimited list instead of a 1:M table relationship the only option is to run a primary query to explode each record (server time heavy) and then run your desired select query.

The best practice solution is to alter the table relationship so that you have a 1:M row relationship to assignto


table workassign
=============
workid: 45
assignto: "1, 2, 3, 4" {remove this column completely after backing up data}




So you have now

table workassign
=============
workid: 45

AND

table workassign_service
=========================
workid: 45
serviceid: 1
***
workid: 45
serviceid: 2
***
workid: 45
serviceid: 3
***
workid: 45
serviceid: 4


By doing so you remove the search inability and you can then utilize the "IN function" and run JUST THE "PRIMARY QUERY".

Otherwise, in lieu of this change, you will need to do a primary "SEARCH LOOP TO EXTRACT IDs" then do a "PRIMARY QUERY"
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LVL 19

Expert Comment

by:NerdsOfTech
ID: 24128315
That or you could utilize a rarely used string function that may help you:

FIND_IN_SET

http://dev.mysql.com/doc/refman/5.1/en/string-functions.html#function_find-in-set
$strsql = "SELECT m.id, DATE_FORMAT(m.mdate,'%m/%d/%Y'), m.item, m.description, m.status, w.assignto, s.sid, s.serviceby FROM maint m left join workassign w on m.id=w.mid left join service s on w.assignto=s.sid WHERE s.username='$loginuser' AND ((FIND_IN_SET(s.sid, (w.assignto)) > 0)";

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