PHP : Update แบบ Join

PHP : Update แบบ Join
Example :
Using IN:

1. UPDATE users
2. SET status='gone'
3. WHERE id IN
4.       ( SELECT userID
5.         FROM usersonline
6.         WHERE timestamp < '$five_ago'
7.       )

Using JOIN:

1. UPDATE users
2.   JOIN usersonline
3.     ON usersonline.userID = users.id
4. SET users.status='gone'
5. WHERE usersonline.timestamp < '$five_ago'
6.  

Using EXISTS:

1. UPDATE users
2. SET status='gone'
3. WHERE EXISTS  
4.       ( SELECT *
5.         FROM usersonline
6.         WHERE timestamp < '$five_ago'
7.           AND userID = users.id
8.       )

เช่น rp_recreatecopy.php

1. $SQL = "";
2. $SQL="UPDATE sci_rp.RPQoute";
3. $SQL.=" JOIN sci_rp.RPLines";
4. $SQL.=" ON RPLines.RPLineId = RPQoute.RPLineId";
5. $SQL.=" SET RPQoute.RPID = '".$NewID."'";
6. $SQL.=" WHERE RPQoute.RPID = '".$RPID."'";
7. $SQL.=" AND RPLines.Status = 'Confirm'";
8. $SQL.=" AND RPLines.RPLineId = RPQoute.RPLineId";
9. $myDB->Update($SQL);

ที่มา http://stackoverflow.com/questions/7988618/php-sql-update-join