DB2中的SQL Concat Distinct结果

Question

I am using the below statement in my query but need to select distinct values in my concatenation string.

substr( 
    xmlserialize( 
        xmlagg( xmltext( concat( ', ', item) ) ) as varchar( 1024 ) 
    ), 
3 )

I have to do it that way because I'm running on a DB2 AS/400 database.

Right now my results look like this:

yellow,red,red,yellow,blue,yellow,blue,red

I need it to return only distinct values, like this:

yellow,red,blue

Answer 1

I figured it out I used a sub select to find the results and than selected from those results the concatention

SELECT 
   CUSTOMER, 
   substr( xmlserialize( xmlagg( xmltext( concat( ', ', item) ) ) as varchar( 1024 ) ), 3)
FROM
   (
SELECT CUSTOMER, ITEM
FROM ORDERS
WHERE
   ITEM LIKE 'C%'
GROUP BY CUSTOMER, ITEM)
GROUP BY CUSTOMER;