不正確的密鑰文件的外部連接邏輯在MySQL

Question

我有一個漫長的MySQL查詢我試圖使用FULL OUTER JOIN上，這並不在MySQL存在：

select c.cat_id,c.cat_name as cat_name, 
c.cat_desc, c.cat_image, mi.filename, 
l.link_id, l.user_id, l.address,l.city, 
l.country,l.link_created,l.link_desc, 
l.email,l.fax,l.link_hits, l.link_modified, 
l.link_name,l.postcode, l.price,l.link_rating, 
l.state,l.telephone,l.link_votes, 
l.website, l.link_id, l.link_visited, cf.value 
from j25_mt_cats as c, 
j25_mt_links as l 
LEFT JOIN j25_mt_cfvalues AS cf ON (cf.link_id = l.link_id), 
j25_mt_images AS mi, 
j25_mt_cl as cl 
where cf.cf_id = 40 and cl.link_id = l.link_id 
AND mi.link_id = l.link_id AND mi.ordering < 2 
AND c.cat_id = cl.cat_id and c.cat_published = 1 
AND c.cat_approved = 1 and l.link_published = 1 and l.link_approved = 1 
ORDER BY RAND() DESC; 

的LEFT JOIN上面是我正在尋找的地方，而不是使用FULL OUTER JOIN邏輯。我知道它必須在UNION中使用多個JOIN，但是我的嘗試導致了各種語法錯誤。

什麼是正確的語法將上述更改爲完整的外部連接邏輯？

我想這一點：

select c.cat_id,c.cat_name as cat_name, 
c.cat_desc, c.cat_image, mi.filename, 
l.link_id, l.user_id, l.address,l.city, 
l.country,l.link_created,l.link_desc, 
l.email,l.fax,l.link_hits, l.link_modified, 
l.link_name,l.postcode, l.price,l.link_rating, 
l.state,l.telephone,l.link_votes, 
l.website, l.link_id, l.link_visited, cf.value 
from j25_mt_cats as c, 
j25_mt_links as l 
LEFT OUTER JOIN j25_mt_cfvalues AS cf ON (cf.link_id = l.link_id), 
j25_mt_images AS mi, 
j25_mt_cl as cl 
UNION ALL 
select c.cat_id,c.cat_name as cat_name, 
c.cat_desc, c.cat_image, mi.filename, 
l.link_id, l.user_id, l.address,l.city, 
l.country,l.link_created,l.link_desc, 
l.email,l.fax,l.link_hits, l.link_modified, 
l.link_name,l.postcode, l.price,l.link_rating, 
l.state,l.telephone,l.link_votes, 
l.website, l.link_id, l.link_visited, cf.value 
FROM j25_mt_cats as c, 
j25_mt_links as l 
RIGHT OUTER JOIN j25_mt_cfvalues AS cf ON cf.link_id = l.link_id, 
j25_mt_images AS mi, 
j25_mt_cl as cl 
where cf.cf_id = 40 and cl.link_id = l.link_id 
AND mi.link_id = l.link_id AND mi.ordering < 2 
AND c.cat_id = cl.cat_id and c.cat_published = 1 
AND c.cat_approved = 1 and l.link_published = 1 and l.link_approved = 1 
AND cf.link_id IS NULL 
ORDER BY RAND() DESC; 

但它需要幾分鐘來運行，然後返回#126 - Incorrect key file for table '/tmp/#sql_4f82_0.MYI'; try to repair it 時，我覺得我更接近正確的語法。磁盤未滿或甚至關閉。這也不是一張表，它只是我在phpMyAdmin中運行的一個查詢。

Answer 1

當您填充臨時目錄時，在您的情況下，您的查詢可能會創建巨大的臨時文件時，會發生此問題。

除了優化您的查詢，請嘗試在您的查詢過程中監視臨時目錄所在的分區show variables like 'tmpdir';。

Answer 2

如果可能的話，請提供表的設計，樣柱，未知列我想的問題是因爲你的底部聯接缺少一些投

select c.cat_id,c.cat_name as cat_name, 
c.cat_desc, c.cat_image, mi.filename, 
l.link_id, l.user_id, l.address,l.city, 
l.country,l.link_created,l.link_desc, 
l.email,l.fax,l.link_hits, l.link_modified, 
l.link_name,l.postcode, l.price,l.link_rating, 
l.state,l.telephone,l.link_votes, 
l.website, l.link_id, l.link_visited, cf.value 
from j25_mt_cats as c, 
j25_mt_links as l 
LEFT OUTER JOIN j25_mt_cfvalues AS cf ON (cf.link_id = l.link_id) 

//你MI這裏missng [開始]

j25_mt_images AS mi, 
j25_mt_cl as cl 
where cf.cf_id = 40 and cl.link_id = l.link_id 
AND mi.link_id = l.link_id AND mi.ordering < 2 
AND c.cat_id = cl.cat_id and c.cat_published = 1 
AND c.cat_approved = 1 and l.link_published = 1 and l.link_approved = 1 
AND cf.link_id IS NULL 

// END

UNION ALL 
select c.cat_id,c.cat_name as cat_name, 
c.cat_desc, c.cat_image, mi.filename, 
l.link_id, l.user_id, l.address,l.city, 
l.country,l.link_created,l.link_desc, 
l.email,l.fax,l.link_hits, l.link_modified, 
l.link_name,l.postcode, l.price,l.link_rating, 
l.state,l.telephone,l.link_votes, 
l.website, l.link_id, l.link_visited, cf.value 

//ü忘了定義C，L，CF在這裏

FROM j25_mt_cats as c, j25_mt_links as l 
RIGHT OUTER JOIN j25_mt_cfvalues as cf ON cf.link_id = l.link_id, 
j25_mt_images AS mi, 
j25_mt_cl as cl 
where cf.cf_id = 40 and cl.link_id = l.link_id 
AND mi.link_id = l.link_id AND mi.ordering < 2 
AND c.cat_id = cl.cat_id and c.cat_published = 1 
AND c.cat_approved = 1 and l.link_published = 1 and l.link_approved = 1 
AND cf.link_id IS NULL 
ORDER BY RAND() DESC;