Ottieni i record degli ultimi 30 giorni dalla data odierna in SQL Server

Aggiungi un'altra condizione in where clause

SELECT * FROM  product 
WHERE pdate >= DATEADD(day,-30,GETDATE()) 
and   pdate <= getdate()

Oppure usa DateDiff

SELECT * FROM  product 
WHERE DATEDIFF(day,pdate,GETDATE()) between 0 and 30