轉換mysql子查詢加入

Question

我是mysql數據庫的新手，我試圖創建一個使用連接的查詢。 我已經寫了，走的時間來執行1秒，當前查詢，我已經做了reasearch，發現加入成爲減少執行的時間最好的解決辦法，

我在用的查詢是：

SELECT count(1) as total 
FROM `mytable` 
where pid IN (
    SELECT pid FROM `maps` 
    where `node_id` = (
      SELECT nid FROM shop 
      WHERE value = 'selling' 
      and parent = '170' 
      and tid = 1 
     ) 
    and tid = 1 
) 
and `pnumber` IN (
    select pnumber 
    FROM users_pro 
    where value = 'hulo' 
    and tid = 1 
) 
and tid = 1 

請大家不要多多幫助。

謝謝..

Answer 1

SELECT count(distinct mytable.*) as total 
FROM mytable 
JOIN maps 
    ON mytable.pid = maps.pid 
    AND maps.tid = mytable.tid 
JOIN shop 
    ON maps.node_id = shop.nid 
    AND shop.value = 'selling' 
    AND shop.parent = '170' 
    AND shop.tid = mytable.tid 
JOIN users_pro 
    ON mytable.pnumber = users_pro.pnumber 
    AND users_pro.value = 'hulo' 
    AND users_pro.tid = mytable.tid 
WHERE mytable.tid=1