Select multiple columns from a table but group by one

Question

The table name is  OrderDetails  and columns are given below   OrderDetailID    ProductID    ProductName    OrderQuantity   I m trying to select multiple columns and Group By ProductID while having SUM of OrderQuantity    Select ProductID ProductName OrderQuantity Sum OrderQuantity   from OrderDetails Group By ProductID   But of course this code gives an error  I have to add other column names to group by  but that s not what I want and since my data has many items so results are unexpected that way   Sample Data Query    ProductID ProductName OrderQuantity from OrderDetails  Results are below    ProductID     ProductName    OrderQuantity     1001          abc               5     1002          abc               23     ProductNames can be same      2002          xyz               8     3004          ytp               15     4001          aze               19     1001          abc               7      2nd row of same ProductID    Expected result    ProductID     ProductName    OrderQuantity     1001          abc               12     group by productID while summing      1002          abc               23     2002          xyz               8     3004          ytp               15     4001          aze               19   How do I select multiple columns and Group By ProductID column since ProductName is not unique    While doing that  also get the sum of the OrderQuantity column

User · Answer

mysql GROUP CONCAT function could help https   dev mysql com doc refman 8 0 en group-by-functions html function group-concat  SELECT ProductID  GROUP CONCAT DISTINCT ProductName  as Names  SUM OrderQuantity  FROM OrderDetails GROUP BY ProductID   This would return   ProductID     Names          OrderQuantity 1001          red            5 1002          red black      6 1003          orange         8 1004          black orange   15   Similar idea as the one  Urs Marian here posted https   stackoverflow com a 38779277 906265

User · Answer

Your Data  DECLARE  OrderDetails TABLE   ProductID INT ProductName VARCHAR 10   OrderQuantity INT   INSERT INTO  OrderDetails VALUES  1001  abc  5   1002  abc  23   2002  xyz  8    3004  ytp  15   4001  aze  19   1001  abc  7    Query   Select ProductID  ProductName  Sum OrderQuantity  AS Total  from  OrderDetails   Group By ProductID  ProductName  ORDER BY ProductID   Result   ---------------------------------     ProductID    ProductName    Total      ----------- ------------- -------           1001    abc               12            1002    abc               23            2002    xyz                8            3004    ytp               15            4001    aze               19     ---------------------------------

User · Answer

You can try this   Select ProductID ProductName Sum OrderQuantity    from OrderDetails Group By ProductID  ProductName   You re only required to Group By columns that doesn t come with an aggregate function in the Select clause  So you can just use Group By ProductID and ProductName in this case

User · Answer

I use this trick to group by one column when I have a multiple columns selection  SELECT MAX id  AS id      Nume      MAX intrare  AS intrare      MAX iesire  AS iesire      MAX intrare-iesire  AS stoc      MAX data  AS data FROM Produse GROUP BY Nume ORDER BY Nume  This works

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EDIT    I checked your question again and have concluded this can t be done   ProductName is not unique  It must either be part of the Group By or excluded from your results   For example how would SQL present these results to you if you Group By only ProductID   ProductID   ProductName   OrderQuantity  --------------------------------------- 1234        abc           1 1234        def           1 1234        ghi           1 1234        jkl           1

User · Answer

In my opinion this is a serious language flaw that puts SQL light years behind other languages  This is my incredibly hacky workaround  It is a total kludge but it always works   Before I do I want to draw attention to  Peter Mortensen s answer  which in my opinion is the correct answer  The only reason I do the below instead is because most implementations of SQL have incredibly slow join operations and force you to break  don t repeat yourself   I need my queries to populate fast   Also this is an old way of doing things  STRING AGG and STRING SPLIT are a lot cleaner  Again I do it this way because it always works   -- remember Substring is 1 indexed  not 0 indexed SELECT ProductId     SUBSTRING         MAX enc pnameANDoq   1  CHARINDEX      MAX enc pnameANDoq   - 1       AS ProductName     SUM   CAST   SUBSTRING         MAX enc pnameAndoq   CHARINDEX      MAX enc pnameANDoq     1  9999       AS INT     AS OrderQuantity FROM       SELECT CONCAT  ProductName       CAST OrderQuantity AS VARCHAR 10          AS pnameANDoq  ProductID     FROM OrderDetails     enc GROUP BY ProductId   Or in plain language     Glue everything except one field together into a string with a delimeter you know won t be used Use substring to extract the data after it s grouped   Performance wise I have always had superior performance using strings over things like  say  bigints  At least with microsoft and oracle substring is a fast operation   This avoids the problems you run into when you use MAX   where when you use MAX   on multiple fields they no longer agree and come from different rows  In this case your data is guaranteed to be glued together exactly the way you asked it to be   To access a 3rd or 4th field  you ll need nested substrings   after the first semicolon look for a 2nd   This is why STRING SPLIT is better if it is available   Note   While outside the scope of your question this is especially useful when you are in the opposite situation and you re grouping on a combined key  but don t want every possible permutation displayed  that is you want to expose  foo  and  bar  as a combined key but want to group by  foo

User · Answer

I just wanted to add a more effective and generic way to solve this kind of problems  The main idea is about working with sub queries  do your group by and join the same table on the ID of the table  your case is more specific since your productId is not unique so there is 2 ways to solve this  I will begin by the more specific solution  Since your productId is not unique we will need an extra step which is to select DISCTINCT product ids after grouping and doing the sub query like following  WITH CTE TEST AS  SELECT productId  SUM OrderQuantity  Total                     FROM OrderDetails                     GROUP BY productId  SELECT DISTINCT OrderDetails ProductID   OrderDetails ProductName  CTE TEST Total FROM OrderDetails  INNER JOIN CTE TEST ON CTE TEST ProductID   OrderDetails ProductID  this returns exactly what is expected  ProductID     ProductName         Total     1001          abc               12         1002          abc               23     2002          xyz               8     3004          ytp               15     4001          aze               19  But there a cleaner way to do this  I guess that ProductId is a foreign key to products table and i guess that there should be and OrderId primary key  unique  in this table  in this case there are few steps to do to include extra columns while grouping on only one  It will be the same solution as following Let s take this t Value table for example   If i want to group by description and also display all columns  All i have to do is   create WITH CTE Name subquery with your GroupBy column and COUNT condition select all or whatever you want to display  from value table and the total from the CTE INNER JOIN with CTE on the ID primary key or unique constraint  column  and that s it  Here is the query WITH CTE TEST AS  SELECT Description  MAX Id  specID  COUNT Description  quantity                      FROM sch dta t value                     GROUP BY Description  SELECT sch dta t Value    CTE TEST quantity  FROM sch dta t Value  INNER JOIN CTE TEST ON CTE TEST specID   sch dta t Value Id  And here is the result

User · Answer

I had a similar problem to the OP  Then I saw the answer from  Urs Marian which helped a lot  But additionally what I was looking for is  when there are multiple values in a column and they will be grouped  how I can get the last submitted value  e g  ordered by a date id column   Example  We have following table structure  CREATE TABLE tablename       msgid   int  NOT NULL       userid   int  NOT NULL       username   varchar  70  NOT NULL       message   varchar  5000  NOT NULL     Now there are at least two datasets in the table   ------- -------- ---------- ---------    msgid   userid   username   message    ------- -------- ---------- ---------        1        1   userA      hello           2        1   userB      world      ------- -------- ---------- ---------   Therefore following SQL script does work  checked on MSSQL  to group it  also if the same userid has different username values  In the example below  the username with the highest msgid will be shown  SELECT m userid    select top 1 username from table where userid   m userid order by msgid desc  as username  count    as messages FROM tablename m GROUP BY m userid ORDER BY count    DESC

User · Answer

SELECT ProductID  ProductName  OrderQuantity  SUM OrderQuantity  FROM OrderDetails WHERE OrderQuantity  IN SELECT SUM OrderQuantity  FROM OrderDetails GROUP BY OrderDetails  GROUP BY ProductID  ProductName  OrderQuantity   I used the above solution to solve a similar problem in Oracle12c

User · Answer

WITH CTE SUM AS         SELECT ProductID  Sum OrderQuantity  AS TotalOrderQuantity        FROM OrderDetails GROUP BY ProductID           SELECT DISTINCT OrderDetails ProductID  OrderDetails ProductName  OrderDetails OrderQuantity CTE SUM TotalOrderQuantity      FROM      OrderDetails INNER JOIN CTE SUM      ON OrderDetails ProductID   CTE SUM ProductID   Please check if this works

User · Answer

You can try the below query  I assume you have a single table for all your data   SELECT OD ProductID  OD ProductName  CalQ OrderQuantity FROM  SELECT DISTINCT ProductID  ProductName       FROM OrderDetails  OD INNER JOIN  SELECT ProductID  OrderQuantity SUM OrderQuantity              FROM OrderDetails             GROUP BY ProductID  CalQ ON CalQ ProductID   OD ProductID

[sql] Select multiple columns from a table, but group by one

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