Take the first line of the every partition - sql-server

Question

I have this query :
select ROW_NUMBER() OVER ( PARTITION BY codtiers ORDER BY case when isnull(cumulapport, 0) > isnull(cumulretrait, 0) then cumulapport
else cumulretrait
end DESC ) AS classement,
codTiers
from dbo.TiersComptesLocal
group by codTiers
which return this result :
classement | codTiers
-------------------------
1 | 1XXXXX
2 | 1XXXXX
1 | 1YYXXX
2 | 1YYXXX
3 | 1YYXXX
1 | 1XXXYY
I want to display the first line from every partition
I want to have a result like this :
classement | codTiers
-------------------------
1 | 1XXXXX
1 | 1YYXXX
1 | 1XXXYY
Any idea will be appreciate.
this is my full query :
select ROW_NUMBER() OVER ( PARTITION BY tcl_codtiers ORDER BY case when isnull(cumulapport, 0) > isnull(cumulretrait, 0) then cumulapport
else cumulretrait
end DESC ) AS classement,
TCL_CodTiers,
'le montant max des ' + Senscumul + ' ( '
+ convert(varchar(50), '') + ' € ) du tiers titulaire '
+ TCL_CodTiers + ' ( ' + ''
+ ' ) est supérieur au seuil fixé dans l''alerte : '
+ '75000'
from dbo.CLI_TCL_TiersComptesLocal
INNER JOIN dbo.CLI_GCO_GeneriquesComptes ON TCL_CodTiers = GCO_CodTiersPrincipal
AND TCL_NumLien IN ( 0, 1 )
inner join ( select TCL_CodTiers CodTiers,
sum(case when ESO_MntValoRetenuEnEuros > 0
then ESO_MntValoRetenuEnEuros
else 0
end) cumulapport,
sum(case when ESO_MntValoRetenuEnEuros < 0
then abs(ESO_MntValoRetenuEnEuros)
else 0
end) cumulretrait,
case when isnull( sum(case when ESO_MntValoRetenuEnEuros > 0
then ESO_MntValoRetenuEnEuros
else 0
end), 0) > isnull( sum(case when ESO_MntValoRetenuEnEuros < 0
then abs(ESO_MntValoRetenuEnEuros)
else 0
end), 0)
then 'Apports'
else 'Retraits'
end as Senscumul
from CRO_ESO_EntreeSortie
inner join CLI_TCL_TiersComptesLocal on TCL_CodCompte = ESO_CodCompte
and TCL_NumLien in ( 0, 1 )
group by TCL_CodTiers
having sum(case when ESO_MntValoRetenuEnEuros > 0
then ESO_MntValoRetenuEnEuros
else 0
end) > 75000
or sum(case when ESO_MntValoRetenuEnEuros < 0
then abs(ESO_MntValoRetenuEnEuros)
else 0
end) > 75000
) surveillance on GCO_CodTiersPrincipal = CodTiers
Thanks in advance.

Answer 1

No idea why you don't want to use a CTE, but you can use a derived table if you want, though it still is basically the same answer that Mahmoud already posted:
SELECT *
FROM (SELECT ROW_NUMBER() OVER (PARTITION BY codtiers
ORDER BY CASE WHEN ISNULL(cumulapport, 0)>ISNULL(cumulretrait, 0)
THEN cumulapport ELSE cumulretrait END DESC) AS classement,
codTiers
FROM dbo.TiersComptesLocal
GROUP BY codTiers) A
WHERE classement = 1

Answer 2

Here is a solution without using WITH - though I'm not sure why that is a problem.
SELECT classement, codtiers
FROM
(
SELECT
classement = ROW_NUMBER() OVER (PARTITION BY codtiers
ORDER BY CASE WHEN ISNULL(cumulapport, 0) > ISNULL(cumulretrait, 0)
THEN cumulapport ELSE cumulretrait END DESC),
codTiers
FROM dbo.TiersComptesLocal
) AS x
WHERE classement = 1;

Answer 3

WITH CTE
AS
(
SELECT
ROW_NUMBER() OVER (PARTITION BY codtiers
ORDER BY CASE
WHEN ISNULL(cumulapport, 0) >
ISNULL(cumulretrait, 0) THEN cumulapport
ELSE cumulretrait
END DESC) AS classement,
codTiers
FROM dbo.TiersComptesLocal
)
SELECT *
FROM CTE
WHERE classement = 1;
Update
You can't filter on that column classement in the same query, you have to use a CTE or a subquery instead like in #AaronBertrand answer. However, if you want to do this in the same query, you have to do this without ROW_NUMBER():
SELECT
codtiers,
MAX(CASE
WHEN ISNULL(cumulapport, 0) >
ISNULL(cumulretrait, 0) THEN cumulapport
ELSE cumulretrait
END DESC) AS classement
FROM dbo.TiersComptesLocal
GROUP BY codtiers;