A Parse Tree Example

$$ Query$>$ :$=$ SELECT FROM $[$ WHERE $]$

select a from $x$ where $b=3$Draw a parse tree for the following SQL statements.

$($a$)$ select a from x where b $=3$

$($b$)$ select a$,$ b from x$,$y$,$z

$($c$)$ delete from x where a $=$ b and c $=0$

$($d$)$ update x set a $=$ bwhere c $=3$

$($e$)$ insert into x $($a$,$b$,$c$)$ values $(3,$ 'glop', $4)$

$($f$)$ create table x $($ a varchar$(3),$ b int, c varchar$(2))$Figure $18-4$

The grammar for the SimpleDB subset of SQL