SQL查詢隨着UNION返回一個小於預期

我使用這個查詢試圖檢索4個畫廊：SQL查詢隨着UNION返回一個小於預期

(SELECT * FROM edgewe_ngg_pictures a, edgewe_ngg_gallery b 
WHERE a.pid = b.previewpic and galleryid = '567' limit 1) 
UNION ALL 
    (SELECT * FROM edgewe_ngg_pictures a, edgewe_ngg_gallery b 
    WHERE a.pid = b.previewpic and galleryid = '541' limit 1) 
UNION ALL 
    (SELECT * FROM edgewe_ngg_pictures a, edgewe_ngg_gallery b 
    WHERE a.pid = b.previewpic and galleryid = '484' limit 1) 
UNION ALL 
    (SELECT * FROM edgewe_ngg_pictures a, edgewe_ngg_gallery b 
    WHERE a.pid = b.previewpic and galleryid = '545' limit 1)

然而，返回3，如果我重複過去的查詢，返回4。任何想法爲什麼？

這工作，但凌亂：

(SELECT * FROM edgewe_ngg_pictures a, edgewe_ngg_gallery b 
WHERE a.pid = b.previewpic and galleryid = '567' limit 1) 
UNION ALL 
     (SELECT * FROM edgewe_ngg_pictures a, edgewe_ngg_gallery b 
     WHERE a.pid = b.previewpic and galleryid = '541' limit 1) 
UNION ALL (SELECT * FROM edgewe_ngg_pictures a, edgewe_ngg_gallery b 
     WHERE a.pid = b.previewpic and galleryid = '484' limit 1) 
UNION ALL 
    (SELECT * FROM edgewe_ngg_pictures a, edgewe_ngg_gallery b 
     WHERE a.pid = b.previewpic and galleryid = '545' limit 1) # 
UNION ALL 
     (SELECT * FROM edgewe_ngg_pictures a, edgewe_ngg_gallery b 
     WHERE a.pid = b.previewpic and galleryid = '545' limit 1)

來源

2014-08-28 Jon Lachonis

謝謝你的編輯邁克爾！ – 2014-08-28 15:07:43

爲什麼不使用IN（567,484，...，545）？並且如果你有欺騙，那麼你會看清楚嗎 – Bulat 2014-08-28 15:08:45

我是一名SQL新手，所以我需要更多解釋你的意思。 – 2014-08-28 15:09:26

嘗試：

SELECT * 
FROM 
edgewe_ngg_pictures p inner join 
edgewe_ngg_gallery g on 
p.pid = g.previewpic 
WHERE 
galleryid in('567','541','484','545')

來源

2014-08-28 15:11:53 Beth

SQL查詢隨着UNION返回一個小於預期

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