Nuts and bolts

SELECT Fields(x1, x2, … , xn)FROM Obj x1 SUCH THAT A1 Obj x2 SUCH THAT A2 …WHERE Condition(x1, x2, … xn)

nested loops join algorithm: for all x1 such that A1 is true for all x2 such that A2 is true …

SELECT Fields(x1, x2, … , xn) FROM Obj x1 SUCH THAT A1 Obj x2 SUCH THAT A2 … WHERE Condition(x1, x2, … xn)