Need help with a SELECT statement - select

Question

I express the relationship between records and searchtags that can be attached to records like so:
TABLE RECORDS
id
name
TABLE SEARCHTAGS
id
recordid
name
I want to be able to SELECT records based on the searchtags that they have. For example, I want to be able to SELECT all records that have searchtags:
(1 OR 2 OR 5) AND (6 OR 7) AND (10)
Using the above data structure, I am uncertain how to structure the SQL to accomplish this.
Any suggestions?
Thanks!

Answer 1

You may want to try the following:
SELECT r.id, r.name
FROM records r
WHERE EXISTS (SELECT NULL FROM searchtags WHERE recordid = r.id AND id IN (1, 2, 5)) AND
EXISTS (SELECT NULL FROM searchtags WHERE recordid = r.id AND id IN (6, 7)) AND
EXISTS (SELECT NULL FROM searchtags WHERE recordid = r.id AND id IN (10));
Test case: Note that only records 1 and 4 will satisfy the query criteria.
CREATE TABLE records (id int, name varchar(10));
CREATE TABLE searchtags (id int, recordid int);
INSERT INTO records VALUES (1, 'a');
INSERT INTO records VALUES (2, 'b');
INSERT INTO records VALUES (3, 'c');
INSERT INTO records VALUES (4, 'd');
INSERT INTO searchtags VALUES (1, 1);
INSERT INTO searchtags VALUES (2, 1);
INSERT INTO searchtags VALUES (6, 1);
INSERT INTO searchtags VALUES (10, 1);
INSERT INTO searchtags VALUES (1, 2);
INSERT INTO searchtags VALUES (2, 2);
INSERT INTO searchtags VALUES (3, 2);
INSERT INTO searchtags VALUES (1, 3);
INSERT INTO searchtags VALUES (10, 3);
INSERT INTO searchtags VALUES (5, 4);
INSERT INTO searchtags VALUES (7, 4);
INSERT INTO searchtags VALUES (10, 4);
Result:
+------+------+
| id | name |
+------+------+
| 1 | a |
| 4 | d |
+------+------+
2 rows in set (0.01 sec)

Answer 2

SELECT
id, name
FROM
records
WHERE
EXISTS (
SELECT 1 FROM searchtags WHERE recordid = records.id AND id IN (1, 2, 5)
)
AND EXISTS (
SELECT 1 FROM searchtags WHERE recordid = records.id AND id IN (6, 7)
)
AND EXISTS (
SELECT 1 FROM searchtags WHERE recordid = records.id AND id IN (10)
)

Answer 3

not sure how to do it in mysql, but in t-sql, you could do something like:
SELECT id, name FROM RECORDS where id in (SELECT recordid from SEARCHTAGS where id in (1,2,5,6,7,10))
I may not be understanding your question entirely... but I gave it my best.

Answer 4

Try:
SELECT R.*
FROM RECORDS R, SEARCHTAGS S
WHERE R.id == S.recordid
AND S.name in (1,2,5,6,7,10);
Don't know if you need S.name or S.id, but this is an example.

Answer 5

select RECORDS.name
from RECORDS join SEARCHTAGS
on RECORDS.id = SEARCHTAGS.recordid
where RECORDS.id in (1,2,...)

Answer 6

I misread the question first time around, and thought it was asking for
(1 AND 2 AND 5) OR (6 AND 7) OR (10)
instead of the correct
(1 OR 2 OR 5) AND (6 OR 7) AND (10)
All the answers so far have concentrated on answering the specific example, rather than addressing the more general question "and suppose I want a different set of criteria next time".
Actual question
I can't do much better than the selected answer for the actual question (Query 1):
SELECT r.id, r.name
FROM Records AS r
WHERE EXISTS(SELECT * FROM SearchTags AS s
WHERE r.id = s.recordid AND s.id IN (1, 2, 5))
AND EXISTS(SELECT * FROM SearchTags AS s
WHERE r.id = s.recordid AND s.id IN (6, 7))
AND EXISTS(SELECT * FROM SearchTags AS s
WHERE r.id = s.recordid AND s.id IN (10));
This could be written as a join to 3 aliases for the SearchTags table.
Alternative question
There are several ways to answer the alternative - I think this is the most nearly neat and extensible. Clearly, the one item (10) is easy (Query 2):
SELECT r.id, r.name
FROM records AS r JOIN searchtags AS t ON r.id = t.recordid
WHERE t.id IN (10) -- or '= 10' but IN is consistent with what follows
The two items (6 or 7) can be done with (Query 3):
SELECT r.id, r.name
FROM records AS r JOIN searchtags AS t ON r.id = t.recordid
WHERE t.id IN (6, 7)
GROUP BY r.id, r.name
HAVING COUNT(*) = 2
The three items (1, 2, 5) can be done with (Query 4):
SELECT r.id, r.name
FROM records AS r JOIN searchtags AS t ON r.id = t.recordid
WHERE t.id IN (1, 2, 5)
GROUP BY r.id, r.name
HAVING COUNT(*) = 3
And the whole collection can be a UNION of the three terms.
Generalizing the solutions
The downside of this solution is that the SQL must be manually crafted for each set of items.
If you want to automate the 'SQL generation', you need the control data - the sets of interesting search tags - in a table:
CREATE TABLE InterestingTags(GroupID INTEGER, TagID INTEGER);
INSERT INTO InterestingTags(1, 1);
INSERT INTO InterestingTags(1, 2);
INSERT INTO InterestingTags(1, 5);
INSERT INTO InterestingTags(2, 6);
INSERT INTO InterestingTags(2, 7);
INSERT INTO InterestingTags(3, 10);
For the query asking for '(1 OR 2 OR 5) AND (...)' (conjunctive normal form), you can write (Query 5):
SELECT r.id, r.name
FROM records AS r JOIN
searchtags AS s ON r.id = s.recordID JOIN
interestingtags AS t ON s.id = t.tagID
GROUP BY r.id, r.name
HAVING COUNT(DISTINCT t.GroupID) = (SELECT COUNT(DISTINCT GroupID)
FROM InterestingTags);
This checks that the number of distinct 'interesting groups of tags' for a given record is equal to the total number of 'interesting groups of tags'.
For the query asking for '(1 AND 2 AND 5) OR (...)' (disjunctive normal form), you can write a join with InterestingTags and check that the Record has as many entries as the group of tags (Query 6):
SELECT i.id, i.name
FROM (SELECT q.id, q.name, c.GroupSize,
COUNT(DISTINCT t.GroupID) AS GroupCount
FROM records AS q JOIN
searchtags AS s ON q.id = s.recordID JOIN
interestingtags AS t ON s.id = t.tagID JOIN
(SELECT GroupID, COUNT(*) AS GroupSize
FROM InterestingTags
GROUP BY GroupID) AS c ON c.GroupID = t.GroupID
GROUP BY q.id, q.name, c.GroupSize
) AS i
WHERE i.GroupCount = i.GroupSize;
Test Data
I took the test data from Daniel Vassalo's answer and augmented it with some extra values:
CREATE TABLE records (id int, name varchar(10));
CREATE TABLE searchtags (id int, recordid int);
INSERT INTO records VALUES (1, 'a');
INSERT INTO records VALUES (2, 'b');
INSERT INTO records VALUES (3, 'c');
INSERT INTO records VALUES (4, 'd');
INSERT INTO records VALUES (11, 'A11');
INSERT INTO records VALUES (21, 'B12');
INSERT INTO records VALUES (31, 'C13');
INSERT INTO records VALUES (41, 'D14');
INSERT INTO records VALUES (51, 'E15');
INSERT INTO records VALUES (61, 'F16');
INSERT INTO searchtags VALUES (1, 1);
INSERT INTO searchtags VALUES (2, 1);
INSERT INTO searchtags VALUES (6, 1);
INSERT INTO searchtags VALUES (10, 1);
INSERT INTO searchtags VALUES (1, 2);
INSERT INTO searchtags VALUES (2, 2);
INSERT INTO searchtags VALUES (3, 2);
INSERT INTO searchtags VALUES (1, 3);
INSERT INTO searchtags VALUES (10, 3);
INSERT INTO searchtags VALUES (5, 4);
INSERT INTO searchtags VALUES (7, 4);
INSERT INTO searchtags VALUES (10, 4);
INSERT INTO searchtags VALUES (1, 11);
INSERT INTO searchtags VALUES (2, 11);
INSERT INTO searchtags VALUES (5, 11);
INSERT INTO searchtags VALUES (6, 21);
INSERT INTO searchtags VALUES (7, 21);
INSERT INTO searchtags VALUES (10, 31);
INSERT INTO searchtags VALUES (1, 41);
INSERT INTO searchtags VALUES (6, 41);
INSERT INTO searchtags VALUES (10, 41);
INSERT INTO searchtags VALUES (2, 51);
INSERT INTO searchtags VALUES (5, 51);
INSERT INTO searchtags VALUES (10, 51);
INSERT INTO searchtags VALUES (7, 61);
INSERT INTO searchtags VALUES (2, 61);
INSERT INTO searchtags VALUES (1, 61);
CREATE TABLE InterestingTags(GroupID INTEGER, TagID INTEGER);
INSERT INTO InterestingTags VALUES(1, 1);
INSERT INTO InterestingTags VALUES(1, 2);
INSERT INTO InterestingTags VALUES(1, 5);
INSERT INTO InterestingTags VALUES(2, 6);
INSERT INTO InterestingTags VALUES(2, 7);
INSERT INTO InterestingTags VALUES(3, 10);
Test results
The outputs that I got were:
Query 1
1 a
4 d
41 D14
Query 2
1 a
3 c
4 d
31 C13
41 D14
51 E15
Query 3
21 B12
Query 4
11 A11
Query 5
1 a
41 D14
4 d
Query 6
4 d
31 C13
3 c
1 a
41 D14
51 E15
Clearly, if I wanted the output in a specific order, I would add an ORDER BY clause to the queries.