Pb avc Syntax Select

Merci de m'apporter votre aide,

Voila mon souci j'ai une procedure stockée dont la syntaxe est la suivante :

declare @Sql varchar(400)

set @SQL='SELECT Op.ReferenceOpe AS Reference, CONVERT(Varchar(10), CAST(Op.DateNego AS datetime), 103) AS DateNego,
CONVERT(Varchar(10), CAST(Ts.DateValeur AS datetime), 103) AS DateVal, Op.CodeCtpie AS Contrepartie, Cp.NomCtpie,
Op.CodeValeur AS CodeValeur, Ts.LibelleValeur AS Description, Op.Nominal AS Nominal, Op.Prix AS Prix,
Op.MntNet AS MntNet, Ts.TauxCC AS CC, Ts.Devise AS DR, Op.CodeAnnul AS Annulation, Op.Sens
FROM T_Operations Op INNER JOIN
T_Titres Ts ON Op.CodeValeur = Ts.CodeValeur INNER JOIN
T_Contreparties Cp ON Op.CodeCtpie = Cp.CodeCtpie'

exec (@Sql)

L'erreur provoqué est :
Server: Msg 107, Level 16, State 2, Line 1
The column prefix 'Op' does not match with a table name or alias name used in the query.
Server: Msg 107, Level 16, State 1, Line 1
The column prefix 'Op' does not match with a table name or alias name used in the query.etc..
et ej ne comprend pas pk vu que les alias sont correctement utilisés.