问题
I'm trying to use this query:
SELECT COUNT(PF.PageID) AS Total,P.PageID FROM Pages P LEFT JOIN Pages_Filters PF ON PF.PageID=P.PageID WHERE P.PageID IN ( (SELECT PageID FROM Pages_Filters WHERE FilterID="1" AND FilterOptionID="2" ), (SELECT PageID FROM Pages_Filters WHERE FilterID="7" AND FilterOptionID="57" ) ) AND P.PageID !="283" GROUP BY PF.PageID
Which produces the error:
Sub-query returns more than 1 row
I'd like for MySQL to merge the results of all the sub-queries, and use values in common as the IN clause in the main query.
So if the first sub-query returns 1,2,4 and the second sub-query returns 2,3,4, then the "in" clause would read:
WHERE P.PageID IN (2,4)
because 2 and 4 are the values the two sub-queries have in common.
Is this possible with one query?
UPDATE:
I'm going to try to clarify the question a bit better.
The result should return all of the pages which have the specified filters set to a specific value INCLUDING pages that have extra filters set which are not part of the query. In other words, I'm on a page with certain filters in place, show me all the pages that I can go to from here that have these same filters, and have one additional filter set.
It's a bit tricky to explain, but I'm looking for a result set that INCLUDES pages with other filters set, but NOT pages with a different value for the same filter ID.
So in the example, we want all pages that have filter 1 set to value 2, AND filter 7 set to 57. We also want pages with other filters (besides 1 and 7) assigned, but NOT pages who have filter 7 set to a value other than 57, and NOT pages who have filter 1 set to a value other than 2.
UPDATE with SAMPLE DATA
Pages_Filters:
PageID FilterID FilterOptionID 297 2 5 297 7 57 297 9 141 305 2 5 101 2 5 101 7 57
Pages:
PageID PageName 297 Some Page 305 Another Page 101 A Stupid Page
In this case I should be able to ask, "What pages have Filter 2 set to 5, also have filter 7 set to 57, and also have filter 9 set to 141"?
The answer should be "only 297".
回答1:
You should be able to "merge" the result sets union UNION/UNION ALL
Something like
SELECT COUNT(PF.PageID) AS Total,P.PageID
FROM Pages P
LEFT JOIN Pages_Filters PF ON PF.PageID=P.PageID
WHERE P.PageID IN (
SELECT PageID
FROM Pages_Filters
WHERE FilterID="1"
AND FilterOptionID="2"
UNION ALL
SELECT PageID
FROM Pages_Filters
WHERE FilterID="7"
AND FilterOptionID="57"
)
AND P.PageID !="283"
GROUP BY PF.PageID
回答2:
SELECT COUNT(PF.PageID) AS Total,P.PageID
FROM Pages P
LEFT JOIN Pages_Filters PF ON PF.PageID=P.PageID
WHERE (PF.FilterID="1"
AND PF.FilterOptionID="2")
OR (PF.FilterID="7"
AND PF.FilterOptionID="57" )
AND P.PageID !="283"
GROUP BY PF.PageID
After thinking and reading Insane's comments I realized that this is maybe what you want. Basically the Derived Table I have created creates the intersection of your two queries above.
SELECT COUNT(PF.PageID) AS Total,P.PageID
FROM Pages P
LEFT JOIN (Select PF1.* from Pages_Filters PF1
INNER JOIN Page_Filters PF2 ON PF1.PageID = PF2.Page_ID
WHERE PF1.FilterID = "1" AND PF2.FilterOptionID = "2"
AND PF2.FilterID = "7" AND PF2.FilterOptionID = "57"
) PF ON PF.PageID=P.PageID
WHERE P.PageID !="283"
GROUP BY PF.PageID
回答3:
Try This
SELECT COUNT(PF.PageID) AS Total,P.PageID
FROM Pages P
LEFT JOIN Pages_Filters PF ON PF.PageID=P.PageID
WHERE P.PageID IN (
SELECT GROUP_CONCAT(DISTINCT(PageID))
FROM Pages_Filters
WHERE (FilterID="1" AND FilterOptionID="2")
AND (FilterID="7" AND FilterOptionID="57")
)
AND P.PageID !="283"
GROUP BY PF.PageID
Or you can try something like
http://dev.mysql.com/doc/refman/5.0/en/exists-and-not-exists-subqueries.html
from this link
回答4:
Isolate the query that produces your list of PageIDs. You need to end up with a single query that returns the values you need. You can do that like this:
SELECT PageID P1 FROM Page_Filters
WHERE FilterID = "1" AND FilterOptionID = "2" AND EXISTS
(SELECT * FROM PageID P2
WHERE P2.PageID = P1.PageID AND FilterID = "7" AND FilterOptionID = "57")
来源:https://stackoverflow.com/questions/4242184/mysql-using-in-with-multiple-subqueries