How to use Oracle CTE for such query?












0















I have a query that looks like following:



SELECT m.Name, (m.Value + NVL(a1.Value1, 0) + NVL(a2.Value2,0) + NVL(a3.Value3,0) "Value"
FROM m MainTable
LEFT JOIN Additional1 a1 ON (...)
LEFT JOIN Additional2 a2 ON (...)
LEFT JOIN Additional3 a3 ON (...)
WHERE (conditions on m)
ORDER BY 1;


These query produces multiple rows for each Name.



I need to limit it to one row for each Name with the following logic: include the row which Value is the closest to the average Value for a given Name.



Something tells me that CTE should allow for a more compact code and hopefully more effective implementation, so I do not need to repeat the virtually same query several times.



Can you please point me into the right direction?










share|improve this question



























    0















    I have a query that looks like following:



    SELECT m.Name, (m.Value + NVL(a1.Value1, 0) + NVL(a2.Value2,0) + NVL(a3.Value3,0) "Value"
    FROM m MainTable
    LEFT JOIN Additional1 a1 ON (...)
    LEFT JOIN Additional2 a2 ON (...)
    LEFT JOIN Additional3 a3 ON (...)
    WHERE (conditions on m)
    ORDER BY 1;


    These query produces multiple rows for each Name.



    I need to limit it to one row for each Name with the following logic: include the row which Value is the closest to the average Value for a given Name.



    Something tells me that CTE should allow for a more compact code and hopefully more effective implementation, so I do not need to repeat the virtually same query several times.



    Can you please point me into the right direction?










    share|improve this question

























      0












      0








      0


      1






      I have a query that looks like following:



      SELECT m.Name, (m.Value + NVL(a1.Value1, 0) + NVL(a2.Value2,0) + NVL(a3.Value3,0) "Value"
      FROM m MainTable
      LEFT JOIN Additional1 a1 ON (...)
      LEFT JOIN Additional2 a2 ON (...)
      LEFT JOIN Additional3 a3 ON (...)
      WHERE (conditions on m)
      ORDER BY 1;


      These query produces multiple rows for each Name.



      I need to limit it to one row for each Name with the following logic: include the row which Value is the closest to the average Value for a given Name.



      Something tells me that CTE should allow for a more compact code and hopefully more effective implementation, so I do not need to repeat the virtually same query several times.



      Can you please point me into the right direction?










      share|improve this question














      I have a query that looks like following:



      SELECT m.Name, (m.Value + NVL(a1.Value1, 0) + NVL(a2.Value2,0) + NVL(a3.Value3,0) "Value"
      FROM m MainTable
      LEFT JOIN Additional1 a1 ON (...)
      LEFT JOIN Additional2 a2 ON (...)
      LEFT JOIN Additional3 a3 ON (...)
      WHERE (conditions on m)
      ORDER BY 1;


      These query produces multiple rows for each Name.



      I need to limit it to one row for each Name with the following logic: include the row which Value is the closest to the average Value for a given Name.



      Something tells me that CTE should allow for a more compact code and hopefully more effective implementation, so I do not need to repeat the virtually same query several times.



      Can you please point me into the right direction?







      sql oracle11g common-table-expression






      share|improve this question













      share|improve this question











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      share|improve this question










      asked Mar 6 '13 at 1:45









      PM 77-1PM 77-1

      8,847144585




      8,847144585
























          1 Answer
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          0














          A CTE can help, but I think the key are the analytic functions. First, you can calculate the average of value for each name using an analytic function. Then you can rank the absolute value of the differences.



          Here is the version with the CTE:



          with t as (
          SELECT m.Name,
          (m.Value + NVL(a1.Value1, 0) + NVL(a2.Value2,0) + NVL(a3.Value3,0) "Value"
          FROM m MainTable
          LEFT JOIN Additional1 a1 ON (...)
          LEFT JOIN Additional2 a2 ON (...)
          LEFT JOIN Additional3 a3 ON (...)
          WHERE (conditions on m)
          )
          select t.*
          from (select t.*,
          row_number() over (partition by name order by avgdiff) as seqnum
          from (select t.*,
          abs(value - avg(value) over (partition by name)) as AvgDiff
          from t
          ) t
          ) t
          where seqnum = 1





          share|improve this answer



















          • 5





            I'm a bit confused here. Why is the "outside" query and both internal queries all have the same alias?

            – PM 77-1
            Mar 6 '13 at 2:09











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          1 Answer
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          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          0














          A CTE can help, but I think the key are the analytic functions. First, you can calculate the average of value for each name using an analytic function. Then you can rank the absolute value of the differences.



          Here is the version with the CTE:



          with t as (
          SELECT m.Name,
          (m.Value + NVL(a1.Value1, 0) + NVL(a2.Value2,0) + NVL(a3.Value3,0) "Value"
          FROM m MainTable
          LEFT JOIN Additional1 a1 ON (...)
          LEFT JOIN Additional2 a2 ON (...)
          LEFT JOIN Additional3 a3 ON (...)
          WHERE (conditions on m)
          )
          select t.*
          from (select t.*,
          row_number() over (partition by name order by avgdiff) as seqnum
          from (select t.*,
          abs(value - avg(value) over (partition by name)) as AvgDiff
          from t
          ) t
          ) t
          where seqnum = 1





          share|improve this answer



















          • 5





            I'm a bit confused here. Why is the "outside" query and both internal queries all have the same alias?

            – PM 77-1
            Mar 6 '13 at 2:09
















          0














          A CTE can help, but I think the key are the analytic functions. First, you can calculate the average of value for each name using an analytic function. Then you can rank the absolute value of the differences.



          Here is the version with the CTE:



          with t as (
          SELECT m.Name,
          (m.Value + NVL(a1.Value1, 0) + NVL(a2.Value2,0) + NVL(a3.Value3,0) "Value"
          FROM m MainTable
          LEFT JOIN Additional1 a1 ON (...)
          LEFT JOIN Additional2 a2 ON (...)
          LEFT JOIN Additional3 a3 ON (...)
          WHERE (conditions on m)
          )
          select t.*
          from (select t.*,
          row_number() over (partition by name order by avgdiff) as seqnum
          from (select t.*,
          abs(value - avg(value) over (partition by name)) as AvgDiff
          from t
          ) t
          ) t
          where seqnum = 1





          share|improve this answer



















          • 5





            I'm a bit confused here. Why is the "outside" query and both internal queries all have the same alias?

            – PM 77-1
            Mar 6 '13 at 2:09














          0












          0








          0







          A CTE can help, but I think the key are the analytic functions. First, you can calculate the average of value for each name using an analytic function. Then you can rank the absolute value of the differences.



          Here is the version with the CTE:



          with t as (
          SELECT m.Name,
          (m.Value + NVL(a1.Value1, 0) + NVL(a2.Value2,0) + NVL(a3.Value3,0) "Value"
          FROM m MainTable
          LEFT JOIN Additional1 a1 ON (...)
          LEFT JOIN Additional2 a2 ON (...)
          LEFT JOIN Additional3 a3 ON (...)
          WHERE (conditions on m)
          )
          select t.*
          from (select t.*,
          row_number() over (partition by name order by avgdiff) as seqnum
          from (select t.*,
          abs(value - avg(value) over (partition by name)) as AvgDiff
          from t
          ) t
          ) t
          where seqnum = 1





          share|improve this answer













          A CTE can help, but I think the key are the analytic functions. First, you can calculate the average of value for each name using an analytic function. Then you can rank the absolute value of the differences.



          Here is the version with the CTE:



          with t as (
          SELECT m.Name,
          (m.Value + NVL(a1.Value1, 0) + NVL(a2.Value2,0) + NVL(a3.Value3,0) "Value"
          FROM m MainTable
          LEFT JOIN Additional1 a1 ON (...)
          LEFT JOIN Additional2 a2 ON (...)
          LEFT JOIN Additional3 a3 ON (...)
          WHERE (conditions on m)
          )
          select t.*
          from (select t.*,
          row_number() over (partition by name order by avgdiff) as seqnum
          from (select t.*,
          abs(value - avg(value) over (partition by name)) as AvgDiff
          from t
          ) t
          ) t
          where seqnum = 1






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Mar 6 '13 at 1:58









          Gordon LinoffGordon Linoff

          766k35300402




          766k35300402








          • 5





            I'm a bit confused here. Why is the "outside" query and both internal queries all have the same alias?

            – PM 77-1
            Mar 6 '13 at 2:09














          • 5





            I'm a bit confused here. Why is the "outside" query and both internal queries all have the same alias?

            – PM 77-1
            Mar 6 '13 at 2:09








          5




          5





          I'm a bit confused here. Why is the "outside" query and both internal queries all have the same alias?

          – PM 77-1
          Mar 6 '13 at 2:09





          I'm a bit confused here. Why is the "outside" query and both internal queries all have the same alias?

          – PM 77-1
          Mar 6 '13 at 2:09


















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