SQL Case Issue Setting Variable - sql-server

Question

Why is it that I can't do the below script and how would I go about fixing it? I get the error Inccorect syntax near '='. I was doing it using ...= 1 THEN 'D' ELSE '' END as Aset but I need to check Aset and Bset in the third Case so I declared Aset and Bset instead.
declare #Aset varchar(10)
declare #Bset varchar(10)
UPDATE m
SET m.new_name = m.new_name + ' ' + #ASet + AndSet + #BSet + ' Type'
FROM contactMaster m
inner join contact c on
m.contactid = c.contactid
CROSS APPLY (
SELECT CASE #Aset WHEN (c.category1|
c.category2|
c.category3|
c.category4) = 1 THEN 'C' ELSE '' End
,CASE #Bset WHEN (c.category5|
c.category6|
c.category7|
c.category8) = 1 THEN 'D' ELSE '' END
,CASE WHEN #BSet = 'D' and #ASet = 'C' THEN ' & ' ELSE '' END AS AndSet
) AS CA1

Answer 1

I don't have your table schema or data, so I had to wing it and couldn't test it, but see if this might work:
UPDATE m
SET m.new_name = m.new_name
+ ' '
+ CA1.ASet
+ CASE WHEN
(
CA1.Aset = 'C' AND
CA1.Bset = 'D'
)
THEN ' & ' ELSE '' END
+ CA1.BSet + ' Type'
FROM contactMaster m
JOIN contact c on m.contactid = c.contactid
CROSS APPLY (
SELECT CASE WHEN
(
c.category1 |
c.category2 |
c.category3 |
c.category4
)
= 1 THEN 'C' ELSE '' END AS Aset,
CASE WHEN
(
c.category5 |
c.category6 |
c.category7 |
c.category8
)
= 1 THEN 'D' ELSE '' END AS Bset
) AS CA1