The Arcive of Official vBulletin Modifications Site.It is not a VB3 engine, just a parsed copy! |
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#1
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Query to select duplicate fields
Hi, I have this:
[sql] SELECT email,username, COUNT(email) AS NumOccurrences FROM user GROUP BY email HAVING ( COUNT(email) > 1 ) [/sql] And it works just fine, but I was wondering how to make it so that it actually LISTS each occurence? For example, it gives me this Quote:
Quote:
Thanks! |
#2
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you're trying to find out how many times any unique email address appears in the db and list the different users that have those same email addresses?
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#3
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Yes. This is with a very old install of vBulletin, btw. I think vB 3.x is set up to never allow duplicate emails.
There are 35 emails that have been used at least twice, some up to 10 times, so I'd want a comprehensive list of the hundred or so usernames that have duplicate emails. The way I'm doing it now only shows me ONE of the usernames attached to the email. I guess I could type out all 35 emails in a query? haha. |
#4
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I'm at work and I don't have access to a MySQL database at the moment, but I think this query will do it for you:
[SQL]SELECT u.username, u.email, count(*) as NumOccurences FROM user u INNER JOIN user u2 ON u.email = u2.email GROUP BY u.username, u.email HAVING count(*) > 1[/SQL] |
#5
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Well, something went screwy and I had to KILL the process. I just about had a panic attack.
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#6
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I ran this this morning on my own forum and it worked fine. It does do a table scan, I noticed. If you have a ton of users, you might try adding an index on the email field if there isn't one there already.
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#7
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You could use group_concat
select username, group_concat(email), count(*) from user group by username having count(*) > 1 |
#8
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Quote:
It ended up looking like: [sql]SELECT email, group_concat( username ) , COUNT( email ) FROM user GROUP BY email HAVING (COUNT( email ) >1)[/sql] |
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