1

I'm doing some data analysis and want to find an easy way to examine all the members of each "group" in a group by function.

Like, 3 agents may be involved in an order. I want to quickly examine the three agents that were 'grouped' in this order for various reasons.

Usually, I would use group_concat for this (easy way to see all grouped strings). However replicating that using a 'group by' appears difficult and unwieldy for now in SQL sever.

Right now, rough-and-dirty, I would max(username) and min(username) to quickly find 2 (and 90% of orders probably have 2 or less people. Is there a way to do mid(username) or 2nd-highest(username), or percentile(50th, username)? That would be a great, quick way to find this relevant data. For some reason, the previous answers I've seen describing group_concat on SQL Server do not sound straightforward to me.

Sample data for instance:

employee  purchase_id
bill        1
bob         1
chrissy     1
mike        2
bill        2
bob         3

Currently I have this:

purchase_id, employee_count, complicated metric
1                 3              blahblah
2                 2                dsflsajf
3                 1                98%

I would like to see at a glance:

purchase_id, employees, complicated metric
1            (bill,bob,chrissy)   blahblah

However the group_concat seems very confusing to use with a group by statement - or simulating group_concat with SQL Server. So instead, how bout this.

select max(employee), min(employee)

purchase_id,  max(employee), min(employee)
1              bill            chrissy

in the example you see that bob is omitted, as max/ min will only find the two endpoints. If there was some kind of function to pull the second highest value, or 50th percentile value, on strings, that would be helpful.

  • Please add some sample data to your question to help us help you. – Randolph West Oct 31 '16 at 21:58
2

Something like this would split the results into multiple columns, but you would need to know in advance the maximum number of employees per purchase_id:

With Ordered_cte As ( 
    Select employee,
        purchase_id,
        RowNo = Row_Number() Over (Partition By purchase_id Order By employee)
      From tbl_purchase_employee)
Select purchase_id,
    Employee1 = Max(iif(RowNo = 1, employee, Null)),
    Employee2 = Max(iif(RowNo = 2, employee, Null)),
    Employee3 = Max(iif(RowNo = 3, employee, Null))
  From Ordered_cte
  Group By purchase_id;
1
SELECT
    t1.purchase_id,
    employees= STUFF((SELECT ','+ employee FROM tbl_employees t2 WHERE t2.purchase_id = t1.purchase_id FOR XML PATH('')) , 1 , 1 , '')

FROM tbl_employees t1
GROUP BY t1.purchase_id

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