SQL displaying results based on a value in column

Question

So I have 2 tables in web SQL , one of them looks like this(there are thousands of rows):

    customer_number        |       order_number
--------------------------------------------
1234                              12
1234                              13
1234                              14
6793                              20
6793                              22
3210                              53

etc.

And the other table like this(also thousands of rows):

customer_number        |       first_purchase_year
----------------------------------------------------
1234                              2010
5313                              2001
1632                              2018
9853                              2017
6793                              2000
3210                              2005

etc.

I have this code to select 10 customers from the first table and list all their purchases:

select top 10 * from
(select distinct t1.customer_number, 
    stuff((select '' + t2.order_number
                from orders t2
                where t1.customer_number = t2.customer_number
                for xml path(''), type
                ).value('.','NVARCHAR(MAX)')
            ,1,0,'')DATA
from orders t1) a

Whch outputs this:

    customer_number        |       order_number
--------------------------------------------
1234                              12 13 14
6793                              20 22
3210                              53

What I need to do is ONLY display 10 random customers that have first_purchase_year > 2010. I am not sure how to check if first_purchase_year corresponding to a customer_number is greater than 2010. Thank you!

Answer 1

You just need to fix the subquery in the outer from clause:

select c.customer_number, 
       stuff((select '' + o2.order_number
              from orders o2
              where c.customer_number = o2.customer_number
              for xml path(''), type
             ).value('.','NVARCHAR(MAX)'
                    ), 1, 0, ''
            ) as data
from (select top (10) c.customer_number
      from table2 c
      where c.first_purchase_year > 2010
     ) c;