$.$ Compare rational algebra joint operations with SQL join statements. $(2$pts$).$

$3.$ Consider the Hotel schema that you had for Question $2$ in Assignment # $1.$ Answer the following

questions $(2$pts$)$:

a$)\backslash$Pi hotelName $($Hotel $$ Hotel.hotelNo $=$ Room.hotelNo $(\backslash$sigma price $>50($Room$)))(1$pts$).$

b$)$ Guest $(\backslash$sigma dateTo $>=1-$Jan$-2007($Booking$))(1$pts$)$