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POCombining mysql queries that recycle multiple self joins
 

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  1. POCombining mysql queries that recycle multiple self joins
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    <p>I have the following set of MySQL queries, used to track user progress through a website. Is there a good way to simplify them?</p> <pre><code>#How many people reached stage 2 SELECT COUNT(DISTINCT a.session_id) as "total" FROM formation_page_hits a WHERE a.progress = 2 AND DATE(a.datetime) = "2011-03-23"; #How many people reached stage 4 having reached stage 2 SELECT COUNT(DISTINCT a.session_id) as "total" FROM formation_page_hits a, (SELECT f.session_id, f.`datetime` FROM formation_page_hits f WHERE f.progress = 2) as b WHERE a.progress = 4 AND a.session_id = b.session_id AND DATE(b.datetime) = "2011-03-23" AND DATE(a.datetime) = "2011-03-23"; #How many people reached stage 7, having reached stage 4, having reached stage 2 SELECT COUNT(DISTINCT a.session_id) as "total" FROM formation_page_hits a, (SELECT f.session_id, f.`datetime` FROM formation_page_hits f WHERE f.progress = 4) as b, (SELECT f.session_id, f.`datetime` FROM formation_page_hits f WHERE f.progress = 2) as c WHERE a.progress = 7 AND a.session_id = b.session_id AND a.session_id = c.session_id AND DATE(c.datetime) = "2011-03-23" AND DATE(b.datetime) = "2011-03-23" AND DATE(a.datetime) = "2011-03-23"; </code></pre> <p>As you can see, I'm very quickly re-querying the same information and there are an additional 4 or 5 queries that follow the same pattern - is there a better way of constructing the query that means I don't have to keep querying for "how many people reached stage 2"?</p> <p><strong>EDIT:</strong> each page view is stored as an entry in formation_page_hits - so that there is a complete record of page views for each session</p> <pre><code>id_formation_page_hits INT PRIMARY_KEY, session_id VARCHAR(100), datetime DATETIME, progress INT </code></pre>
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    1. USJon
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    1. COCan we cache the results in the form of temp table?
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      1. USNitin Midha
    2. COCan a `session_id` have more than record for any `progress`?
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    3. COYes, each `session_id` has multiple entries (one for each page view within that session) - each page has a specific `progress` number attached to it
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