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POset column value based on distinct values in another column
 

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  1. POset column value based on distinct values in another column
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    <p>I am trying to do something very similar to this question: <a href="https://stackoverflow.com/questions/4908245/mysql-updateing-row-based-on-other-rows">mysql - UPDATEing row based on other rows</a></p> <p>I have a table, called modset, of the following form:</p> <pre><code>member year y1 y2 y3 y1y2 y2y3 y1y3 y1y2y3 a 1 0 0 0 0 0 0 0 a 2 0 0 0 0 0 0 0 a 3 0 0 0 0 0 0 0 b 1 0 0 0 0 0 0 0 b 2 0 0 0 0 0 0 0 c 1 0 0 0 0 0 0 0 c 3 0 0 0 0 0 0 0 d 2 0 0 0 0 0 0 0 </code></pre> <p>Columns 3:9 are binary flags to indicate which combination of years the member has records in. So I wish the result of an SQL update to look as follows:</p> <pre><code>member year y1 y2 y3 y1y2 y2y3 y1y3 y1y2y3 a 1 0 0 0 0 0 0 1 a 2 0 0 0 0 0 0 1 a 3 0 0 0 0 0 0 1 b 1 0 0 0 1 0 0 0 b 2 0 0 0 1 0 0 0 c 1 0 0 0 0 0 1 0 c 3 0 0 0 0 0 1 0 d 2 0 1 0 0 0 0 0 </code></pre> <p>The code in the question linked above does something very close but only when it is a count of the distinct years in which the member has records. I need to base the columns on the specific values of the years in which the member has records.</p> <p>Thanks in advance!</p> <p><strong>SOLUTION</strong></p> <pre><code>SELECT member, case when min(distinct(year)) = 1 and max(distinct(year)) = 1 then 1 else 0 end y1, case when min(distinct(year)) = 1 and max(distinct(year)) = 2 then 1 else 0 end y1y2, case when min(distinct(year)) = 1 and max(distinct(year)) = 3 and count(distinct(year)) = 2 then 1 else 0 end y1y3, case when min(distinct(year)) = 1 and max(distinct(year)) = 3 and count(distinct(year)) = 3 then 1 else 0 end y1y2y3, case when min(distinct(year)) = 2 and max(distinct(year)) = 2 then 1 else 0 end y2, case when min(distinct(year)) = 2 and max(distinct(year)) = 3 then 1 else 0 end y2y3, case when min(distinct(year)) = 3 then 1 else 0 end y3 INTO temp5 FROM modset GROUP BY member; UPDATE modset M SET y1 = T.y1, y2 = T.y1, y3 = T.y3, y1y2 = T.y1y2, y1y3 = T.y1y3, y2y3 = T.y2y3, y1y2y3 = T.y1y2y3 FROM temp5 T WHERE T.member = M.member; </code></pre>
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