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我有两个针对同一个表运行的查询，除了第二个因添加左连接而失败。

成功运行

 SELECT *
 FROM paypal_ipn_orders 
 LEFT join itemkey on paypal_ipn_orders.item_number = itemkey.item_id 
 WHERE packing_slip_printed = 0
 AND LOWER(payment_status) = 'completed'
 AND address_name <> ''
 order by itemkey.sort_id;

然而，第二个查询因“'on 子句'中的“未知列'paypal_ipn_orders.item_number'”而失败，但它在没有左连接的情况下运行良好。Paypal_ipn_orders 表确实包含 item_number 字段。

SELECT *
FROM paypal_ipn_orders as table1,
(SELECT payer_email, COUNT(*) as count FROM paypal_ipn_orders GROUP BY payer_email ORDER BY count DESC) as table2
LEFT join itemkey on table1.item_number = itemkey.item_id 
WHERE table1.payer_email = table2.payer_email 
and packing_slip_printed = 0
AND LOWER(payment_status) = 'completed'
AND address_name <> ''
ORDER BY count DESC, auction_multi_item, item_number;

table1 后面的逗号是必需的，因为 (SELECT... 是 FROM 子句的一部分。

一个有趣的笔记。我将 From 子句的顺序更改为：

SELECT *
FROM (SELECT payer_email, COUNT(*) as count FROM paypal_ipn_orders GROUP BY payer_email ORDER BY count DESC) as table1,
paypal_ipn_orders as table12
LEFT join itemkey on table2.item_number = itemkey.item_id 
WHERE table2.payer_email = table1.payer_email 
and packing_slip_printed = 0
AND LOWER(payment_status) = 'completed'
AND address_name <> ''
ORDER BY count DESC, auction_multi_item, item_number;

现在错误消息是：'where 子句'中的未知列'table2.payer_email'。但这不会在没有左连接的情况下运行。在 where 子句消息中给出相同的 Unknown 列。

仅供参考 - 这有效：

 SELECT payer_email, COUNT(*) as count 
 FROM paypal_ipn_orders 
 WHERE packing_slip_printed = 0
 AND LOWER(payment_status) = 'completed'
 AND address_name <> ''
 GROUP BY payer_email 
 ORDER BY count DESC;
4

2 回答 2

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FROM paypal_ipn_orders table1,

你的意思是…… FROM paypal_ipn_orders AS table1 (...？

还要注意 . 末尾的逗号table1,。我不确定这是不是故意的？

于 2013-02-24T02:27:25.830 回答
0

这最终奏效了：

SELECT *
        FROM (SELECT payer_email, COUNT(*) as count 
           FROM paypal_ipn_orders 
           Where packing_slip_printed = 0
           AND LOWER(payment_status) = 'completed'
           AND address_name <> '' 
           GROUP BY payer_email 
           ORDER BY count DESC) as table1,
        paypal_ipn_orders as table2
        LEFT join itemkey on table2.item_number = itemkey.item_id 
        WHERE table1.payer_email = table2.payer_email 
        and packing_slip_printed = 0
        AND LOWER(payment_status) = 'completed'
        AND address_name <> ''
        ORDER BY count DESC, auction_multi_item, sort_id
于 2013-02-26T00:27:32.500 回答