無法執行工會，得到＃1248 - 每一個派生表必須有它自己的別名錯誤

Question

我有這兩個查詢

select 
    t . *, events.event_time as last_time 
from 
    events, 
(
    (
     select 
      bonding.type, 
       bonding.global_id2 as target_post, 
       bonding.target_id as on_whose_post, 
       GROUP_CONCAT(bonding.shooter_id) as shooter_ids, 
       GROUP_CONCAT(bonding.what_global_id) as shooted_what, 
       MAX(bonding.what_global_id) as last, 
       'bonding' as flag 
     from 
      bonding 
     where 
      bonding.type = 1 
       and bonding.shooter_id in (select 
        `user2` 
       from 
        relation_table 
       where 
        `user1` = 192) 
     group by bonding.global_id2 
    ) 
    union 
    (
    select 
      bonding.type, 
       bonding.global_id2 as target_post, 
       bonding.target_id as on_whose_post, 
       GROUP_CONCAT(bonding.shooter_id) as shooter_ids, 
       GROUP_CONCAT(bonding.what_global_id) as shooted_what, 
       MAX(bonding.what_global_id) as last, 
       'bonding' as flag 
     from 
      bonding 
     where 
      bonding.type = 2 
       and bonding.shooter_id in (select 
        `user2` 
       from 
        relation_table 
       where 
        `user1` = 192) 
     group by bonding.global_id2 
    ) 
    union 
    (
    select 
      bonding.type, 
       bonding.global_id2 as target_post, 
       bonding.target_id as on_whose_post, 
       GROUP_CONCAT(bonding.shooter_id) as shooter_ids, 
       GROUP_CONCAT(bonding.what_global_id) as shooted_what, 
       MAX(bonding.what_global_id) as last, 
       'bonding' as flag 
     from 
      bonding 
     where 
      bonding.type = 5 
       and bonding.shooter_id in (select 
        `user2` 
       from 
        relation_table 
       where 
        `user1` = 192) 
     group by bonding.global_id2 
    ) 
    union 
    (
    select 
      bonding.type, 
       bonding.global_id2 as target_post, 
       bonding.target_id as on_whose_post, 
       GROUP_CONCAT(bonding.shooter_id) as shooter_ids, 
       GROUP_CONCAT(bonding.what_global_id) as shooted_what, 
       MAX(bonding.what_global_id) as last, 
       'bonding' as flag 
     from 
      bonding 
     where 
      bonding.type = 9 
       and bonding.shooter_id in (select 
        `user2` 
       from 
        relation_table 
       where 
        `user1` = 192) 
     group by bonding.global_id2 
    ) 
    union 
    (
    select 
      bonding.type, 
       bonding.global_id2 as target_post, 
       bonding.target_id as on_whose_post, 
       GROUP_CONCAT(bonding.shooter_id) as shooter_ids, 
       GROUP_CONCAT(bonding.what_global_id) as shooted_what, 
       MAX(bonding.what_global_id) as last, 
       'bonding' as flag 
     from 
      bonding 
     where 
      bonding.type = 10 
       and bonding.shooter_id in (select 
        `user2` 
       from 
        relation_table 
       where 
        `user1` = 192) 
     group by bonding.global_id2 
    ) 

)as t where events.global_id = t1.last 

等一個： -

SELECT 
    post_stream.type, 
    post_stream.ref_global_id as target_post, 
    post_stream.user_id as on_whose_post, 
    post_stream.user_id as shooter_ids, 
    post_stream.ref_global_id as shooted_what, 
    post_stream.ref_global_id as last, 
    'stream' as flag, 
    events.event_time as last_time 
FROM 
    post_stream, 
    events, 
    relation_table 
WHERE 
    events.global_id = post_stream.ref_global_id 
     and post_stream.type IN (2 , 3, 7, 8) 
     AND post_stream.user_id = relation_table.user2 
     AND relation_table.user1 = 192 

現在我需要執行兩個查詢的聯合以獲得組合結果，但它給出了 每個派生表都必須有它自己的別名錯誤，我應該爲派生表放置一個別名，這兩個查詢在單獨運行時運行時沒有錯誤。

Answer 1

第一個查詢的格式爲長約116行，包含一個5向UNION子查詢。這5個子查詢似乎與WHERE子句中的一個值相同。這個重寫將SQL簡化爲：

SELECT t.type, t.target_post, t.on_whose_post, t.shooter_ids, t.shooted_what, 
     t.last, t.flag, events.event_time AS last_time 
    FROM events JOIN 
     (SELECT bonding.type, 
       bonding.global_id2 AS target_post, 
       bonding.target_id AS on_whose_post, 
       GROUP_CONCAT(bonding.shooter_id) AS shooter_ids, 
       GROUP_CONCAT(bonding.what_global_id) AS shooted_what, 
       MAX(bonding.what_global_id) AS last, 
       'bonding' AS flag 
      FROM bonding 
     WHERE bonding.TYPE IN (1, 2, 5, 9, 10) 
      AND bonding.shooter_id IN (SELECT user2 FROM relation_table WHERE user1 = 192) 
     GROUP BY bonding.global_id2 
     ) AS t 
    ON events.global_id = t1.last 

這將更容易與第二個查詢結合起來。隨着進一步的修訂，我可能會刪除bonding.前綴，因爲主子查詢中唯一的表是bonding。

SELECT p.type   AS type, 
     p.ref_global_id AS target_post, 
     p.user_id  AS on_whose_post, 
     p.user_id  AS shooter_ids, 
     p.ref_global_id AS shooted_what, 
     p.ref_global_id AS last, 
     'stream'  AS flag, 
     e.event_time AS last_time 
    FROM post_stream AS p 
    JOIN events   AS e ON e.global_id = p.ref_global_id 
    JOIN relation_table AS r ON p.user_id = r.user2 
WHERE r.user1 = 192 
    AND post_stream.type IN (2 , 3, 7, 8) 

問題：

第二個查詢應使用JOIN符號也被改寫

1. 你肯定on_whose_post和shooter_ids應該從同一列？
2. 您確定shooted_what和last應該來自同一列嗎？

這樣做可能是有效的（也不是太牽強）的原因 - 但這並不明顯。

不幸的是，我們還沒有被告知如何將第一個查詢中的數據與第二個查詢連接起來。似乎有很多相同的列，只有OP可以確定需要什麼。