Fields disappeared from Grid / FieldPositions

Using SQL SERVER 2012
The problem occurs when using a query with TOP … and a global variable enclosed in single quotes ‘[…]’
The fields do not appear in Grid / FieldPositions
Example:
SELECT TOP 5 rc.DataRic, rc.NoteAzioni,rc.DataEff,ma.codpercric,rc.CodOperatRic FROM RicCli rc
LEFT JOIN mio_assegnaric ma ON ma.codric=rc.Codice
WHERE rc.CodSito=’[codsito]’
ORDER BY rc.Codice DESC