Simple Nested Loop Join

$$\begin{array}{rl}\text{for each record}{r}_i\text{in R:}& \\ \text{for each record}{s}_j\text{in S:}& \\ \text{if}\theta (r_i,s_j):& \text{yield}<r_i,s_j>\end{array}$$

COST = $[R]+|\mathbf{R}|[S]$