What will be the SQL query for this UPDATE operation? -

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i using mysql 5.1. have database tables users , users_group_mapping.

user table :     userid, username,   points      1       user1       10      2       user2       21      3       user3       7      4       user4       44  users_group_mapping table  :     userid, usergroupid      1       1      2       2      4       2      4       1      4       3

and in allocation process have allocate points corresponding groups users. test data :

data : $dtarr = array(     [1] => 40,     [2] => 80,     [3] => 100 )

in array $dtarr, key attribute 'usergroupdid' in users_group_mapping table , value attribute points updated in users table.

e.g. if usergroupid = 2 , points given = 40 users_group_mapping table users in usergroup '2' - userids '2' & '4' - both users 40 points each. userid '4' 40 points allocated through usergroup '2' though user belongs usergoups '1' & '3' also.

what sql update query operation?

please guide me..!! in advance.!!

if have in database , if want in order given table users_group_mapping, should add sequence column table , create new table data. have this:

user table :     userid, username,   points      1       user1       10      2       user2       21      3       user3       7      4       user4       44  users_group_mapping table  :     userid, usergroupid  rowseq      1       1            1      2       2            2      4       2            3      4       1            4      4       3            5  data table  :     usergroupid, points      1             40      2             80        3            100

than sql require follows:

update user    join users_group_mapping using (userid)    join data on data.usergroupid=users_group_mapping.usergroupid   left join users_group_mapping x on x.userid=user.userid , x.rowseq < users_group_mapping.rowseq    set user.points = user.points + data.points   x.userid null

if not want add points existing points, set them, of course use

update user    join users_group_mapping using (userid)    join data on data.usergroupid=users_group_mapping.usergroupid   left join users_group_mapping x on x.userid=user.userid , x.rowseq < users_group_mapping.rowseq    set user.points = data.points   x.userid null

edit

here solution if can not change data structure (php+mysql)

$userids[] = array(); $result = mysql_query("select * user");  while ($row = mysql_fetch_assoc($result)) {   $userids[] = $user_row['userid']; };  foreach($userids $userid) {   $result = mysql_query("select usergroupid  users_group_mapping userid = $userid");   $row = mysql_fetch_assoc($result));   # need first matching row no cycle   $usergroupid = intval($row['usergroupid']);   $points = $dtarr[$usergroupid];   mysql_query("update user set points = points + $points user.userid = $userid");    };

please not although code correct, because not hard solve this, there stupid mistakes (syntax errors etc) not have time debug it. should give answer.


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