ผมขอตัวอย่าง การ select ซ้อน select มี่ท่านใดพอแนะนำ หรือ ให้ตัวอย่างได้ หรือเปล่า ครับ

select * 
from table1 
where table1.id 
in (
select table2.id from table2
)

$rs_group = mysql_query("SELECT   count(order_generation)    AS    V_TOTAL1   ,    SUM(size_new)   AS   V_TOTAL  , check_status  , order_ID  ,order_generation    AS    V_TOTAL2      FROM        genneration_size        
WHERE       check_status='0'      or      check_status='1'      or       check_status='2'        AND     order_generation     IN    ('ASD', 'CSD', 'HRG', 'LBG', 'LSD', 'OBD', 'PFR', 'RAL', 'WSG', '$hdata')          
 GROUP   BY     order_generation");
while($row_group = mysql_fetch_array($rs_group))
{
	$rs_menu = mysql_query("SELECT   count(order_generation)    AS    V_TOTAL_new1   ,    SUM(size_new)   AS   V_TOTAL_new  , check_status  , order_ID      ,order_generation    AS    V_TOTAL2_    FROM        genneration_size    WHERE  check_status='0'      or      check_status='1'     AND    order_generation='$V_result3'     AND     order_generation       IN      ('ASD', 'CSD', 'HRG', 'LBG', 'LSD', 'OBD', 'PFR', 'RAL', 'WSG', '$hdata')       AND      order_generation = ".$row_group['order_generation']."    
	 GROUP   BY     order_generation");
	while($row_menu = mysql_fetch_array($rs_menu))
	{	
	 	echo $row_menu['order_generation'];	 
	} 
}

AND      order_generation = ".$row_group['order_generation']."

AND      order_generation = '".$row_group['order_generation']."'