Find other rows most closely associated with a column





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1















I'm sorry, I'm not sure how to phrase this question.



I have a table with two columns: tag and activity_id used to track a many-to-many relationship between activities and tags. (In reality, tag is actually a numeric tag_id, but I'm simplifying this for the purposed of the question - I can figure out the JOIN later.)



Sample data:



tag, activity_id
"Ideation",52698
"Adult",52698
"Trans man",52698
"USA - Northwest",52698
"Transfeminine",52699
"Ideation",52699
"Adult",52702
"Trans man",52702
"USA - Northwest",52702
"Ideation",52702
"PTSD",52702
"Religious abuse / trauma",52702
"Adult",52709
"Ideation",52709


What I want to find is which tags appear most with others. For example, in the above Ideation and Adult appear with the same activity_id multiple times. Ideation and Trans Man also show up together. What I'd like is a query to show which tags are clustered together based on activity_id, ideally with some sort of rank based on how many times they appear together.



Thanks for any assistance - Please comment if I haven't explained this clearly enough!










share|improve this question





























    1















    I'm sorry, I'm not sure how to phrase this question.



    I have a table with two columns: tag and activity_id used to track a many-to-many relationship between activities and tags. (In reality, tag is actually a numeric tag_id, but I'm simplifying this for the purposed of the question - I can figure out the JOIN later.)



    Sample data:



    tag, activity_id
    "Ideation",52698
    "Adult",52698
    "Trans man",52698
    "USA - Northwest",52698
    "Transfeminine",52699
    "Ideation",52699
    "Adult",52702
    "Trans man",52702
    "USA - Northwest",52702
    "Ideation",52702
    "PTSD",52702
    "Religious abuse / trauma",52702
    "Adult",52709
    "Ideation",52709


    What I want to find is which tags appear most with others. For example, in the above Ideation and Adult appear with the same activity_id multiple times. Ideation and Trans Man also show up together. What I'd like is a query to show which tags are clustered together based on activity_id, ideally with some sort of rank based on how many times they appear together.



    Thanks for any assistance - Please comment if I haven't explained this clearly enough!










    share|improve this question

























      1












      1








      1








      I'm sorry, I'm not sure how to phrase this question.



      I have a table with two columns: tag and activity_id used to track a many-to-many relationship between activities and tags. (In reality, tag is actually a numeric tag_id, but I'm simplifying this for the purposed of the question - I can figure out the JOIN later.)



      Sample data:



      tag, activity_id
      "Ideation",52698
      "Adult",52698
      "Trans man",52698
      "USA - Northwest",52698
      "Transfeminine",52699
      "Ideation",52699
      "Adult",52702
      "Trans man",52702
      "USA - Northwest",52702
      "Ideation",52702
      "PTSD",52702
      "Religious abuse / trauma",52702
      "Adult",52709
      "Ideation",52709


      What I want to find is which tags appear most with others. For example, in the above Ideation and Adult appear with the same activity_id multiple times. Ideation and Trans Man also show up together. What I'd like is a query to show which tags are clustered together based on activity_id, ideally with some sort of rank based on how many times they appear together.



      Thanks for any assistance - Please comment if I haven't explained this clearly enough!










      share|improve this question














      I'm sorry, I'm not sure how to phrase this question.



      I have a table with two columns: tag and activity_id used to track a many-to-many relationship between activities and tags. (In reality, tag is actually a numeric tag_id, but I'm simplifying this for the purposed of the question - I can figure out the JOIN later.)



      Sample data:



      tag, activity_id
      "Ideation",52698
      "Adult",52698
      "Trans man",52698
      "USA - Northwest",52698
      "Transfeminine",52699
      "Ideation",52699
      "Adult",52702
      "Trans man",52702
      "USA - Northwest",52702
      "Ideation",52702
      "PTSD",52702
      "Religious abuse / trauma",52702
      "Adult",52709
      "Ideation",52709


      What I want to find is which tags appear most with others. For example, in the above Ideation and Adult appear with the same activity_id multiple times. Ideation and Trans Man also show up together. What I'd like is a query to show which tags are clustered together based on activity_id, ideally with some sort of rank based on how many times they appear together.



      Thanks for any assistance - Please comment if I haven't explained this clearly enough!







      sql database postgresql






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 16 '18 at 17:38









      Chris GaraffaChris Garaffa

      897




      897
























          1 Answer
          1






          active

          oldest

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          3














          I think you want a self-join and aggregation:



          select s1.tag, s2.tag, count(*)
          from sample s1 join
          sample s2
          on s1.activity_id = s2.activity_id and s1.tag < s2.tag
          group by s1.tag, s2.tag
          order by count(*) desc;





          share|improve this answer
























          • This is amazing, thank you. It's exactly what I needed. Here's the full query I used, with the JOIN I left out above to simplify the example: SELECT t1.tag, t2.tag, s1.tag_id, s2.tag_id, count(*) FROM activities_tags s1 JOIN activities_tags s2 ON s1.activity_id = s2.activity_id AND s1.tag_id < s2.tag_id JOIN tags t1 ON s1.tag_id = t1.id JOIN tags t2 ON s2.tag_id = t2.id GROUP BY t1.tag, t2.tag, s1.tag_id, s2.tag_id ORDER BY count(*) desc;

            – Chris Garaffa
            Nov 16 '18 at 17:57












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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          3














          I think you want a self-join and aggregation:



          select s1.tag, s2.tag, count(*)
          from sample s1 join
          sample s2
          on s1.activity_id = s2.activity_id and s1.tag < s2.tag
          group by s1.tag, s2.tag
          order by count(*) desc;





          share|improve this answer
























          • This is amazing, thank you. It's exactly what I needed. Here's the full query I used, with the JOIN I left out above to simplify the example: SELECT t1.tag, t2.tag, s1.tag_id, s2.tag_id, count(*) FROM activities_tags s1 JOIN activities_tags s2 ON s1.activity_id = s2.activity_id AND s1.tag_id < s2.tag_id JOIN tags t1 ON s1.tag_id = t1.id JOIN tags t2 ON s2.tag_id = t2.id GROUP BY t1.tag, t2.tag, s1.tag_id, s2.tag_id ORDER BY count(*) desc;

            – Chris Garaffa
            Nov 16 '18 at 17:57
















          3














          I think you want a self-join and aggregation:



          select s1.tag, s2.tag, count(*)
          from sample s1 join
          sample s2
          on s1.activity_id = s2.activity_id and s1.tag < s2.tag
          group by s1.tag, s2.tag
          order by count(*) desc;





          share|improve this answer
























          • This is amazing, thank you. It's exactly what I needed. Here's the full query I used, with the JOIN I left out above to simplify the example: SELECT t1.tag, t2.tag, s1.tag_id, s2.tag_id, count(*) FROM activities_tags s1 JOIN activities_tags s2 ON s1.activity_id = s2.activity_id AND s1.tag_id < s2.tag_id JOIN tags t1 ON s1.tag_id = t1.id JOIN tags t2 ON s2.tag_id = t2.id GROUP BY t1.tag, t2.tag, s1.tag_id, s2.tag_id ORDER BY count(*) desc;

            – Chris Garaffa
            Nov 16 '18 at 17:57














          3












          3








          3







          I think you want a self-join and aggregation:



          select s1.tag, s2.tag, count(*)
          from sample s1 join
          sample s2
          on s1.activity_id = s2.activity_id and s1.tag < s2.tag
          group by s1.tag, s2.tag
          order by count(*) desc;





          share|improve this answer













          I think you want a self-join and aggregation:



          select s1.tag, s2.tag, count(*)
          from sample s1 join
          sample s2
          on s1.activity_id = s2.activity_id and s1.tag < s2.tag
          group by s1.tag, s2.tag
          order by count(*) desc;






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 16 '18 at 17:40









          Gordon LinoffGordon Linoff

          797k37318423




          797k37318423













          • This is amazing, thank you. It's exactly what I needed. Here's the full query I used, with the JOIN I left out above to simplify the example: SELECT t1.tag, t2.tag, s1.tag_id, s2.tag_id, count(*) FROM activities_tags s1 JOIN activities_tags s2 ON s1.activity_id = s2.activity_id AND s1.tag_id < s2.tag_id JOIN tags t1 ON s1.tag_id = t1.id JOIN tags t2 ON s2.tag_id = t2.id GROUP BY t1.tag, t2.tag, s1.tag_id, s2.tag_id ORDER BY count(*) desc;

            – Chris Garaffa
            Nov 16 '18 at 17:57



















          • This is amazing, thank you. It's exactly what I needed. Here's the full query I used, with the JOIN I left out above to simplify the example: SELECT t1.tag, t2.tag, s1.tag_id, s2.tag_id, count(*) FROM activities_tags s1 JOIN activities_tags s2 ON s1.activity_id = s2.activity_id AND s1.tag_id < s2.tag_id JOIN tags t1 ON s1.tag_id = t1.id JOIN tags t2 ON s2.tag_id = t2.id GROUP BY t1.tag, t2.tag, s1.tag_id, s2.tag_id ORDER BY count(*) desc;

            – Chris Garaffa
            Nov 16 '18 at 17:57

















          This is amazing, thank you. It's exactly what I needed. Here's the full query I used, with the JOIN I left out above to simplify the example: SELECT t1.tag, t2.tag, s1.tag_id, s2.tag_id, count(*) FROM activities_tags s1 JOIN activities_tags s2 ON s1.activity_id = s2.activity_id AND s1.tag_id < s2.tag_id JOIN tags t1 ON s1.tag_id = t1.id JOIN tags t2 ON s2.tag_id = t2.id GROUP BY t1.tag, t2.tag, s1.tag_id, s2.tag_id ORDER BY count(*) desc;

          – Chris Garaffa
          Nov 16 '18 at 17:57





          This is amazing, thank you. It's exactly what I needed. Here's the full query I used, with the JOIN I left out above to simplify the example: SELECT t1.tag, t2.tag, s1.tag_id, s2.tag_id, count(*) FROM activities_tags s1 JOIN activities_tags s2 ON s1.activity_id = s2.activity_id AND s1.tag_id < s2.tag_id JOIN tags t1 ON s1.tag_id = t1.id JOIN tags t2 ON s2.tag_id = t2.id GROUP BY t1.tag, t2.tag, s1.tag_id, s2.tag_id ORDER BY count(*) desc;

          – Chris Garaffa
          Nov 16 '18 at 17:57




















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