Eliminate null results from case query - no null values in source

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I am trying to pull off a complicated aggregation and concatenation query to prep data for import to a website, aggregating multiple results rows and columns into one row per ID.

I'm almost there, except that I am getting a lot of NULL results despite there being no NULL values in the source data.

Source data:

id value_1 value_2 value_3 type
x1 sometext othertext moretext A2
x1 sometext othertext moretext B1
x1 sometext othertext moretext B2
x2 sometext othertext moretext B1
x2 sometext othertext moretext A2
x2 sometext othertext moretext B1

The following:

select distinct id, 
case when type='A2' then string_agg (concat(cast (value_1 as nvarchar (max)),value_1,value_2,value_3)) end as type_A2, 
case when type='B1' then string_agg (concat(cast (value_1 as nvarchar (max)),value_1,value_2,value_3)) end as type_B1
from source
group by id, type

Produces:

id type_a2 type_B1
x1 sometextothertextmoretext NULL
x1 NULL sometextothertextmoretext
x2 sometextothertextmoretext NULL
x2 NULL sometextothertextmoretext

When I try only running one column at a time, I still get some NULL results.

How do I get these results into one row per unique ID?

ie...

id type_a2 type_B1
x1 sometextothertextmoretext sometextothertextmoretext
x2 sometextothertextmoretext sometextothertextmoretext
x3 etc etc


from Recent Questions - Stack Overflow https://ift.tt/34PElTB
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