[statement_hint_expr] UPDATE table_name [table_hint_expr] [[AS] alias]
SET update_item [, ...]
WHERE condition [return_clause];

update_item: column_name = { expression | DEFAULT }

statement_hint_expr: '@{' statement_hint_key = statement_hint_value '}'

table_hint_expr: '@{' table_hint_key = table_hint_value '}'

return_clause:
    THEN RETURN [ WITH ACTION [ AS alias ]  ] { select_all | expression [  [ AS ] alias ] } [, ...]

select_all:
    [ table_name. ]*
    [ EXCEPT ( column_name [, ...] ) ]
    [ REPLACE ( expression [ AS ] column_name [, ...] ) ]