Question

我需要有关复杂查询的帮助。我有一个Venues表，一个Tag表和一个Venues_Tag_lookup表。当我在屏幕上显示单个场地的细节时，我希望能够展示与当前场地类似的其他场地。

这将需要一个返回前五个场地的查询，这些场地拥有最多匹配的标签。（我正在使用MSSQL）

这是我的表格外观的简单布局。

Venues_tbl
----------
VenueId
Venue_name

Tag_tbl
---------
TagId
Tag_name

Venues_Tag_lookup
------------------
Venue_tagId
VenueId
TagId

如果您有任何疑问，请询问。

提前致谢。

Answer 1

SELECT TOP 5
   V.Venue_name
FROM
   -- this = tags for this venue
   Venues_Tag_lookup this
   JOIN
   -- others = tags for other venues
   Venues_Tag_lookup others
            --see what matches, there will be a big pile of them
            ON this.TagId = others.TagId
   JOIN
   Venues_tbl V ON others.VenueID = V.VenueID
WHERE
   --filter to this and others
   this.VenueID = @TheOneOnScreen
   AND
   others.VenueID <> @TheOneOnScreen
GROUP BY
   --collapse to other venues ...
   V.Venue_name
ORDER BY
   -- ... and simply COUNT matches
   COUNT(*) DESC

Answer 2

以下查询可能有所帮助：

-- params = @venueId, @tagId

select
        venueId,
        venueName,
        (select count * from venues_tag_lookup vtl where vtl.venueid=v.venueid )tagCount
from venues_tbl v
where venueId in(
  select venueId from Venues_tag_lookup where tagId = @tagId
)
and venueId  @venueId
order by 3 desc

SQL - 复杂的查询查询

2 个答案: