如何将这两个查询合并为一个优化查询以避免选择N + 1

Question

This is for an online photo library. I have two tables; "photoSearch" and "photos". The first, "photoSearch", has just a few columns and contains all searchable data for the photos, such as "photoID", "headline", "caption", "people", "dateCaptured" and "keywords". It has a multi-column full-text index on (headline, caption, people, keywords). The second table, "photos", contains all of the photos data; heights, widths, copyrights, caption, ID's, dates and much more. Both have 500K+ rows and the headline and caption fields sometimes return 2000+ characters.

This is approximately how the query looks now: (things to note: I cannot use joins with fulltext searching, hence keywords being stored in one column - in a 'de-normalized' table. Also, this kind of pseudo code as my app code is elsewhere - but it's close )

This particular query is being looped through and inside the loop, another SQL statement is being executed...

 SELECT photoID FROM photoSearch
 WHERE MATCH (headline, caption, people, keywords)
 AGAINST ('"&booleanSearchStr&"' IN BOOLEAN MODE)
 AND dateCaptured BETWEEN '"&fromDate&"' AND '"&toDate&"';"

This is the SQL Statement being executed for each row in the query above:

 SELECT photoID, setID, eventID, locationID, headline, caption, instructions, dateCaptured, dateUploaded, status, uploaderID, thumbH, thumbW, previewH, previewW, + more 
 FROM photos 
 LEFT JOIN events AS e USING (eventID) 
 LEFT JOIN location AS l USING (locationID) 
 WHERE photoID = " & photoID & ";"

When tested, having the full-text index on its own table, "photoSearch", instead of the large table, "photos", seemed to improve speed somewhat. I didn't add the "photoSearch" table, it was already there - this is not my app. If I try joining the two tables to lose the second query, I lose my indexing all together, resulting in very long times - so I can't use joins with full-text. This just seemed to be the quickest method. If it wasn't for the full-text and joining problems, I would have combined both of these queries already.

Is it possible to combine these two queries into one, to make the process run more efficiently, rather than executing query #2 1000 times for each result in query 1?

Answer 1

If a Join didn't work, try a subquery:

SELECT photoID, setID, eventID, locationID, headline, caption, instructions, dateCaptured, dateUploaded, status, uploaderID, thumbH, thumbW, previewH, previewW, + more 
FROM (
    SELECT photoID 
    FROM photoSearch
    WHERE
        MATCH (headline, caption, people, keywords)
            AGAINST ('"&booleanSearchStr&"' IN BOOLEAN MODE)
        AND dateCaptured BETWEEN '"&fromDate&"' AND '"&toDate&"';"
) as SelectedPhotos
LEFT JOIN photos USING (photoID)
LEFT JOIN events AS e USING (eventID) 
LEFT JOIN location AS l USING (locationID)

or try to find out why the join didn't work, i should have used:

SELECT photoID, setID, eventID, locationID, headline, caption, instructions, dateCaptured, dateUploaded, status, uploaderID, thumbH, thumbW, previewH, previewW, + more 
FROM photoSearch
LEFT JOIN photos USING (photoID)
LEFT JOIN events AS e USING (eventID) 
LEFT JOIN location AS l USING (locationID)
WHERE
    MATCH (headline, caption, people, keywords)
        AGAINST ('"&booleanSearchStr&"' IN BOOLEAN MODE)
    AND dateCaptured BETWEEN '"&fromDate&"' AND '"&toDate&"';"