If I put single quote i have an error:

Msg 1023, Level 15, State 1, Procedure pa_CalendarioGestion, Line 34

Invalid parameter 1 specified for datediff.

Msg 1023, Level 15, State 1, Procedure pa_CalendarioGestion,...

Thanks, but @fechaInicio is a parameter of the stored procedure, and I need that work with the format dd/mm/yyyy, because I have more than 30 stored procedures with this format.

declare @fechaInicio smalldatetime

declare @i int

declare @diaActual smalldatetime