根據特定列/字段的隨機值獲取記錄-MySQL

Question

我有以下查詢：

SELECT a.*,
ps4_media.filename,
ps4_galleries.name as galleryname,
ps4_media_iptc.description,
ps4_media_iptc.title,
ps4_media_iptc.headline,
ps4_media.date_added,
ps4_galleries.created,
ps4_folders.name as foldername,
ps4_galleries.gallery_count 
FROM ps4_media_galleries a 
INNER JOIN (SELECT ps4_media_galleries.gallery_id,
min(ps4_media_galleries.gmedia_id) AS minID 
FROM ps4_media_galleries GROUP BY ps4_media_galleries.gallery_id) b 
ON a.gallery_id = b.gallery_id 
AND a.gmedia_id = b.minID
INNER JOIN ps4_media ON ps4_media.media_id = a.gmedia_id 
INNER JOIN ps4_folders ON ps4_folders.folder_id = ps4_media.folder_id
INNER JOIN ps4_galleries ON ps4_galleries.gallery_id = a.gallery_id
INNER JOIN ps4_media_iptc ON ps4_media_iptc.media_id = a.gmedia_id
ORDER BY ps4_galleries.created DESC

我如何獲得ps4_media.filename是隨機的，其他一切都很好，只是想要ps4_media.filename將是縮略圖以及發現集中的記錄。

Answer 1

您需要通過RAND()來排序選擇內容：

SELECT a.*,
ps4_media.filename,
ps4_galleries.name as galleryname,
ps4_media_iptc.description,
ps4_media_iptc.title,
ps4_media_iptc.headline,
ps4_media.date_added,
ps4_galleries.created,
ps4_folders.name as foldername,
ps4_galleries.gallery_count FROM ps4_media_galleries a INNER JOIN (SELECT ps4_media_galleries.gallery_id,
min(ps4_media_galleries.gmedia_id) AS minID FROM ps4_media_galleries GROUP BY ps4_media_galleries.gallery_id) b ON a.gallery_id = b.gallery_id AND a.gmedia_id = b.minID
INNER JOIN ps4_media ON ps4_media.media_id = a.gmedia_id INNER JOIN ps4_folders ON ps4_folders.folder_id = ps4_media.folder_id
INNER JOIN ps4_galleries ON ps4_galleries.gallery_id = a.gallery_id
INNER JOIN ps4_media_iptc ON ps4_media_iptc.media_id = a.gmedia_id
ORDER BY RAND()

Answer 2

該答案基於表設計上的大量 假設 ，因為您的問題中未提及架構或數據流hirarch。

我以一個例子來說明您需要對查詢執行的操作。 如您所見，此設計是一種平滑的設計，其中可能有許多交叉引用，依此類推。 因此，我再次重申自己的觀點，即通過顯示自己的模式來幫助您至關重要。

-- image belongs to a media 
-- folder has many images
---- folder belongs to a media
-- gallery has many media

表格設計：

-- Gallery Table
GID     GNAME       GLOCATION
1       art         cambridge
2       art         torronto
3       picture     melbourne
4       sculpture   paris

-- Media Table
MID     MNAME   MGID
10      screen  1
15      brail   2
20      embose  1
25      print   3
30      print   4
35      embose  2

-- Folder Table
FID     FNAME       FMID
200     fprojToro1  15
201     fprojMelb1  25
202     fprojCamb1  20
203     fprojCamb2  20
204     fprojToro2  15
205     fprojToro3  35
206     fprojMelb2  25
207     fprojMelb3  25

-- Image Table
IID     INAME   IFID
1001    tb01    200
1002    mp02    201
1005    te05    205
1008    te08    205
1010    mp10    206
1015    mp15    207
1018    te18    205

查詢1：

-生成一個隨機文件名

select iname from image
order by Rand()
limit 1
;

結果1：

INAME
tb01

查詢2：

-由於我使用了左聯接-並且某些圖像屬於同一文件夾-在以下查詢中有可能獲得超過-1條記錄

select g.*, m.mname, f.fname, i.iname
from gallery g
left join media m
on m.mgid = g.gid
left join folder f
on f.fmid = m.mid
left join image i
on i.ifid = f.fid
where i.iname = (select iname from image
                 order by Rand()
                 limit 1)
;

結果2：

GID     GNAME   GLOCATION   MNAME   FNAME        INAME
3       picture     melbourne   print   fprojMelb2  mp10

查詢3：

-再次將主查詢限制為1

select g.*, m.mname, f.fname, i.iname
from gallery g
left join media m
on m.mgid = g.gid
left join folder f
on f.fmid = m.mid
left join image i
on i.ifid = f.fid
where i.iname = (select iname from image
                 order by Rand()
                 limit 1)
limit 1
;

結果3：

GID     GNAME   GLOCATION   MNAME   FNAME       INAME
2       art     torronto    embose  fprojToro3  te18