MS SQL Case nesting error but not nested - sql

Question

I got a problem on MS SQL :
I'm using a CASE with many statements in my view, like this :
select
e.[Nom d'annuaire],
e.[Prénom annuaire],
f.[Nom d'annuaire en UTF-8] AS login,
e.Usagers as [Numéro interne],
d.[Numéro externe],
s.[Préfixe No abr direct],
v.fonction,
CASE
WHEN v.lib_delegation = 'Service informatique' THEN 'Euralille'
WHEN v.delegation = 'test_national' THEN 'Maillot'
WHEN v.delegation = 'test_tpe' THEN 'Maillot'
WHEN v.delegation = 'test_paris-idf' THEN 'Maillot'
WHEN v.delegation = 'test_grands-comptes' THEN 'Maillot'
WHEN v.delegation = 'cotestrm' THEN 'Marcq en baroeul'
WHEN v.delegation = 'test_sud-ouest' THEN 'Bruges'
WHEN v.delegation = 'test_normandie' THEN 'Caen'
WHEN v.delegation = 'test_bourgogne' THEN 'Dijon'
WHEN v.delegation = 'test_ouest' THEN 'Ouest'
WHEN v.lib_delegation = 'Centre Limousin' THEN 'Tours'
WHEN v.delegation = 'test_est' THEN 'Nancy'
WHEN v.delegation = 'test_mediterranee' THEN 'Aix'
WHEN v.delegation = 'test_rhone-alpes' THEN 'Lyon'
ELSE v.delegation
END AS Délégation,
v.lib_delegation
from ale e
INNER JOIN ale f
on e.Usagers = f.Usagers AND f.[No alias] = 1 and e.[No Alias] = 0
INNER JOIN Delegation d
on f.Usagers = d.[No annuaire]
INNER JOIN V_users v
on v.LOGIN = f.[Nom d'annuaire en UTF-8]
LEFT OUTER JOIN svi s
on e.Usagers = s.[No d'appel]
order by e.Usagers
As you can see, my CASE statements aren't nasted, because I'm using WHEN... THEN ... syntax and then I simply put ELSE ... END statement.
However, when I try to filter my output using for example filter :
WHERE [Délégation] = 'Euralille'
I just get 2 errors :
Msg 8180, Level 16, State 1, Line 1
Msg 125, Level 15, State 4, Line 1
Explanation of the Error Numbers:
Msg 8180 = Statement(s) could not be prepared.
Msg 125 = Case expressions may only be nested to level %d.
(Sorry for the poor french traduction)
I've been looking for the answer on MS SQL Website, and on StackOverflow but the problem is always that the CASE statements are nasted. But to me, I'm not in this situation...
Thanks in advance, I'm quite a beginner in this world.

Answer 1

Did you filter like this? Note that I put all of your query into a subquery and then applied the where clause afterwards:
select * from
(select
e.[Nom d'annuaire],
e.[Prénom annuaire],
f.[Nom d'annuaire en UTF-8] AS login,
e.Usagers as [Numéro interne],
d.[Numéro externe],
s.[Préfixe No abr direct],
v.fonction,
CASE
WHEN v.lib_delegation = 'Service informatique' THEN 'Euralille'
WHEN v.delegation = 'test_national' THEN 'Maillot'
WHEN v.delegation = 'test_tpe' THEN 'Maillot'
WHEN v.delegation = 'test_paris-idf' THEN 'Maillot'
WHEN v.delegation = 'test_grands-comptes' THEN 'Maillot'
WHEN v.delegation = 'cotestrm' THEN 'Marcq en baroeul'
WHEN v.delegation = 'test_sud-ouest' THEN 'Bruges'
WHEN v.delegation = 'test_normandie' THEN 'Caen'
WHEN v.delegation = 'test_bourgogne' THEN 'Dijon'
WHEN v.delegation = 'test_ouest' THEN 'Ouest'
WHEN v.lib_delegation = 'Centre Limousin' THEN 'Tours'
WHEN v.delegation = 'test_est' THEN 'Nancy'
WHEN v.delegation = 'test_mediterranee' THEN 'Aix'
WHEN v.delegation = 'test_rhone-alpes' THEN 'Lyon'
ELSE v.delegation
END AS Délégation,
v.lib_delegation
from ale e
INNER JOIN ale f
on e.Usagers = f.Usagers AND f.[No alias] = 1 and e.[No Alias] = 0
INNER JOIN Delegation d
on f.Usagers = d.[No annuaire]
INNER JOIN V_users v
on v.LOGIN = f.[Nom d'annuaire en UTF-8]
LEFT OUTER JOIN svi s
on e.Usagers = s.[No d'appel]
order by e.Usagers) as subTotalQuery
WHERE [Délégation] = 'Euralille'