這個查詢有什麼問題？我得到空結果

Question

SELECT `acart`.`order_number` AS `admin_order_number`, 
     `acart`.`user_id` AS `admin_user_id`, 
     `acart`.`created_by` AS `admin_created_by`, 
     `rcart`.`order_number` AS `renew_order_number`, 
     `rcart`.`user_id` AS `renew_user_id`, 
     `rcart`.`created_by` AS `renew_created_by`, 
     `scart`.`order_number` AS `shopping_order_number`, 
     `scart`.`user_id` AS `shopping_user_id`, 
     `scart`.`created_by` AS `shopping_created_by` 
FROM `cdp_order_transaction_master` AS `master` 
LEFT JOIN `cdp_admin_shopping_cart` AS `acart` 
    ON `acart`.`order_number`=`master`.`order_number` 
LEFT JOIN `cdp_renew_cart` AS `rcart` 
    ON `rcart`.`order_number`=`master`.`order_number` 
LEFT JOIN `cdp_shopping_cart` AS `scart` 
    ON `scart`.`order_number`=`master`.`order_number` 
WHERE master.order_number IS NULL 

讓我解釋一下我的問題，如果訂單是全成那麼它會去根據不同的情況，但如果隨後的秩序無法cdp_order_transaction_master表和其他3臺（cdp_admin_shopping_cart，cdp_renew_cart，cdp_shopping_cart）它不會去cdp_order_transaction_master表，並留在其他表， 所以我要失敗的順序是不存在的cdp_order_transaction_master，可以出現在任何其他表（cdp_admin_shopping_cart，cdp_renew_cart，cdp_shopping_c藝術）

Answer 1

WHERE master.order_number IS NULL

這是你的主表，一個d所有其他表的連接條件都在此列上。

您試圖加入空爲空

基於您的評論，請嘗試：

select 'cdp_admin_shopping_cart' as `err_table`, a1.order_number 
from cdp_admin_shopping_cart a1 
where not exists (select 1 from cdp_order_transaction_master a2 where a2.order_number = a1.order_number) 

union all 

select 'cdp_renew_cart' as `err_table`, a1.order_number 
from cdp_renew_cart a1 
where not exists (select 1 from cdp_order_transaction_master a2 where a2.order_number = a1.order_number) 

union all 

select 'cdp_shopping_c‌​art' as `err_table`, a1.order_number 
from cdp_shopping_c‌​art a1 
where not exists (select 1 from cdp_order_transaction_master a2 where a2.order_number = a1.order_number)