MYSQL: greatest-n-per-group issue

Question

Problem of greatest-n-per-group and my MySQL version cannot use the LIMIT & IN (error 1235), so I need to use this kind of query (see answer here: answer )

SELECT
                t1.idMemberCard,
                DATE(MIN(transactions.dateTransaction)) AS first_transaction,
                DATE(MAX(transactions.dateTransaction)) AS last_transaction,
                t2.*
                FROM membersCard AS t1
                INNER JOIN transactions ON transactions.idMemberCard = t1.idMemberCard
                INNER JOIN
                (
                    SELECT
                        membersCard.idMemberCard,
                        membersCard.cardNumber,
                        membersCard.firstNameMemberCard,
                        membersCard.lastNameMemberCard,
                        transactions.dateTransaction
                    FROM membersCard
                    INNER JOIN transactions ON transactions.idMemberCard = membersCard.idMemberCard
                    WHERE membersCard.sexMemberCard = 'M'
                    AND membersCard.cardNumber = '1100101308655'
                    AND
                    DATE(transactions.dateTransaction) BETWEEN ('2013-12-28') AND ('2014-08-13')
                    LIMIT 100
                ) AS t2
                ON t1.idMemberCard = t2.idMemberCard

Subquery (t2 table) executed for exact match (card Number) returns exactly 5 rows (in this example): all perfect.

My issue/request:

Joining the two tables I would to obtain 5 rows and not only one, with the different 5 rows with the dates.

score 0 · Answer 1 · answered Oct 08 '14 at 12:12

0

Your join is working fine. The problem is your select statement:

 SELECT t1.idMemberCard,
        DATE(MIN(transactions.dateTransaction)) AS first_transaction,
        DATE(MAX(transactions.dateTransaction)) AS last_transaction,
        t2.*

The use of MIN() and MAX() turn this into an aggregation query that returns only one row. Try this:

 SELECT t1.idMemberCard,
        DATE(transactions.dateTransaction) AS first_transaction,
        DATE(transactions.dateTransaction) AS last_transaction,
        t2.*

Or add a group by clause if you want that.

answered Oct 08 '14 at 12:12

Gordon Linoff

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@sineverba . . . Then add the appropriate `group by`. – Gordon Linoff Oct 08 '14 at 12:17
If I add "GROUP BY " t1.idMemberCard (same with t2.idMemberCard) I obtain only 1 row. I need 5 rows for the cardNumber "1100101308655" – sineverba Oct 08 '14 at 12:19

MYSQL: greatest-n-per-group issue

1 Answers1