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POCan Someone Help me Optimize this mysql statement?
 

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  1. POCan Someone Help me Optimize this mysql statement?
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    <p>I have one table that I'm using to build groups with in my database. The table contains a list of group names and ids. I have another table that has users, and a third table showing the relationships. (userid, groupid).</p> <p>The situation is this, I need to create a list of userids that belong to a specific subset of groups. So for instance, I want all users that are in group 1, 3, and 8. That is straight forward enough. It gets more complicated though, I may need a list of all users that are in groups 1, 3, and 8, or 1, 2, and 8. Then I might need to exclude users that fit that criteria, but are also in group 27.</p> <p>So I've got a script dynamically creating a query, using sub queries that works to a point. I have two problems with it. I don't think I'm handling the not-in part properly, because as I ad criteria, eventually, it just kinda hangs. (I think this is a result of me using sub-selects instead of joins, but I could not figure out how to build this with joins.)</p> <p>Here is an example of a query with 4 ANDed OR groups, and 2 NOT clauses.</p> <p>Please let me know if there is a better way to optimize this stmt. (I can handle the dynamic building of it in PHP)</p> <p>If I need to clarify anything or provide more details, let me know.</p> <pre><code> select * from users_table where username IN ( select user_id from ( select distinct user_id from group_user_map where user_id in ( select user_id from ( select * from ( select count(*) as counter, user_id from ( ( select distinct(user_id) from group_user_map where group_id in (2601,119) ) union all ( select distinct(user_id) from group_user_map where group_id in (58,226) ) union all ( select distinct(user_id) from group_user_map where group_id in (1299,525) ) union all ( select distinct(user_id) from group_user_map where group_id in (2524,128) ) ) thegroups group by user_id ) getall where counter = 4 ) getuserids ) and user_id not in ( select user_id from group_user_map where group_id in (2572) ) ) biggergroup ); </code></pre> <p>Note, the first part of the query is comparing an id to a username. This is because I have the usernames stored as id's from the other table. (This whole thing is a link between two completely different databases).</p> <p>(Also, if it looks like I have any extra sub-queries, that was to try to force mysql to evaluate the inner queries first.)</p> <p>Thanks.</p> <p>Aaron.</p>
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    1. USSilicaGel
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      1. POCan Someone Help me Optimize this mysql statement?
      1. USSilicaGel
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    1. COSilica, what does mean group_id IN (2601,119). I'd imagine you at this point are looking for just one group (1, 3 or 8). Why do you have a IN and 2 ids?
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      1. USmedina
    2. COAaron, I don't think this does what you think it does. I suggest you provide a simplified version of the problem in the form of a set of CREATE and INSERT statements, the search criteria, and the desired resultset.
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      1. USStrawberry
    3. COPlease provide script structure/data sample for these tables.
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      1. POCan Someone Help me Optimize this mysql statement?
      1. USRonak Vyas
 

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