สอบถามเกี่ยวกับการ Join ตาราง DataBase คับ คือ ผมอยาก Join ตาราง ทั้ง 3 ตาราง ไม่รู้ทำไง

SELECT A.name_drug,A.total_sale,B.total_quantity
FROM 
(
SELECT name_drug, mode, sum(quantity) As total_quantity 
FROM drug 
  INNER JOIN mode 
    ON drug.id_mode = mode.id_mode 
GROUP BY name_drug, mode 
HAVING(sum(quantity) <= 2)
) A 
INNER JOIN 
(
   SELECT name_drug,sum(quantity_sale) as total_sale
   FROM drug_sale
   GROUP BY name_drug
) B 
ON A.name_drug = B.name_drug
WHERE B.total_sale > A.total_quantity

select a.name_drug,sum(quantity) as qty,mode

 from drug a,drug_sale b,mode c

where a.id_drug = b.id_drug and a.id_mode = c.id_mode

group by a.name,mode

 having sum(b.quantity_sale)  > sum(a. quantity)

SELECT a.name_drug, quantity,quantity_sale, mode
FROM drug AS a, drug_sale AS b, mode AS c
WHERE a.id_drug=b.id_drug And a.id_mode=c.id_mode

select a.name_drug,sum(quantity) as qty,mode from drug as a,mode as b
where a.id_mode = b.id_mode
and a.id_drug = (select distinct  id_drug from drug_sale where id_drug = a.id_drug group by id_drug having  sum(quantity_sale) >=  sum(a.quantity) )
Group By a.name_drug,mode

cmd.CommandText = "SELECT info_com(comID,IP_Address,Computer_Name,User_Login,location)" & _
                              ",[เมนบอร์ด].[รหัส] as [รหัสเมนบอร์ด],[เมนบอร์ด].[รหัสอุปกรณ์_Serial] as [รหัสอุปกรณ์_Serialเมนบอร์ด],[เมนบอร์ด].Socket as [Socketเมนบอร์ด],[เมนบอร์ด].[ยี่ห้อ/รุ่น] as [ยี่ห้อ/รุ่นเมนบอร์ด] " & _
                              ",cpu.[รหัส] as [รหัสซีพียู],cpu.[รหัสอุปกรณ์_Serial] as [รหัสอุปกรณ์_Serialซีพียู],cpu.[Socket] as [Socketซีพียู],cpu.[ยี่ห้อ/รุ่น] as [ยี่ห้อ/รุ่นซีพียู] " & _
                              ",ram.[รหัส] as [รหัสแรม],ram.[รหัสอุปกรณ์_Serial] as [รหัสอุปกรณ์_Serialแรม],ram.[บัส],ram.[ยี่ห้อ/รุ่น] as [ยี่ห้อ/รุ่นแรม] " & _
                              ",hdd.[รหัส] as [รหัสhdd],hdd.[รหัสอุปกรณ์_Serial] as [รหัสอุปกรณ์_Serialhdd],hdd.[ความจุ_GB],hdd.[ยี่ห้อ/รุ่น] as [ยี่ห้อ/รุ่นhdd] " & _
                              ",vga.[รหัส] as [รหัสvga],vga.[รหัสอุปกรณ์_Serial] as [รหัสอุปกรณ์_Serialvga],vga.[ความจำ],vga.[ยี่ห้อ/รุ่น] as [ยี่ห้อ/รุ่นvga] " & _
                              ",[power].[รหัส] as [รหัสpower],[power].[รหัสอุปกรณ์_Serial] as [รหัสอุปกรณ์_Serialpower],[power].[wat],[power].[ยี่ห้อ/รุ่น] as [ยี่ห้อ/รุ่นpower] " & _
                              " FROM info_com JOIN [เมนบอร์ด] on info_com.comID = [เมนบอร์ด].inforID" & _
                              ",JOIN cpu  on info_com.comID = cpu.inforID " & _
                              ",JOIN ram on info_com.comID = ram.inforID " & _
                              ",JOIN hdd on info_com.comID = hdd.inforID " & _
                              ",JOIN vga on info_com.comID = vga.inforID " & _
                              ",JOIN [power] on info_com.comID = [power].inforID" & _
                              " where info_com.comID = '" & id & "'" & _
                              " GROUP BY comID"

" FROM info_com JOIN [เมนบอร์ด] on info_com.comID = [เมนบอร์ด].inforID" & _
",JOIN cpu on info_com.comID = cpu.inforID " & _
",JOIN ram on info_com.comID = ram.inforID " & _
",JOIN hdd on info_com.comID = hdd.inforID " & _
",JOIN vga on info_com.comID = vga.inforID " & _
",JOIN [power] on info_com.comID = [power].inforID" & _

" FROM info_com JOIN [เมนบอร์ด] on info_com.comID = [เมนบอร์ด].inforID" & _
" INNER JOIN cpu on info_com.comID = cpu.inforID " & _
" INNER JOIN ram on info_com.comID = ram.inforID " & _
" INNER JOIN hdd on info_com.comID = hdd.inforID " & _
" INNER JOIN vga on info_com.comID = vga.inforID " & _
" INNER JOIN [power] on info_com.comID = [power].inforID" & _