This is saying that an
offset_clause can either be the word
OFFSET followed by an
a_expr, the rule for a general relational expression in this grammar, or the word
OFFSET followed by a
c_expr (a restricted form of
row_or_rows, a rule that expands to either the word
ROW or the word
ROWS, a testament to just how flexible SQL's syntax can sometimes be.
$$ represents the output value of the current rule, $1 the value of the first symbol in the current rule, $2 the value of the second symbol, etc.
- STEP only needs to be added to SELECT statements, not DELETE or UPDATE.
- Remember to add the STEP keyword to one of the keyword category lists at the end of the grammar (this has to be done whenever a new keyword is added).
Type-Checking: Ensuring STEP's arguments are typed as integers