# Basic symbols of relational algebra

Apologies in advance but this blog might start to look like online revision notes (and a LaTeX scratchpad) for the next six weeks.

Projection

$\Pi_{field1, field2, \ldots fieldn} ( D )$

Selection

$\sigma_{field1=condition \wedge field2=condition}(D)$

Rename

$\rho ( E ( \bar F ) , D )$

Conditional Join

$D \Join _{field1 = condition} E$

Natural Join

$D \Join E$

(Page 100 onwards of Database Management Systems, Third Edition)