Add support for FETCH/OFFSET syntax

In terms of syntax, this is what the spec says:

A <query expression> can also optionally contain a <result offset clause>, 
which may limit the cardinality of the derived table by removing a specified 
number of rows from the beginning of the derived table. If a <query expression> 
contains both an <order by clause> and a <result offset clause>, then the rows 
in the derived table are first sorted according to the <order by clause> and then
 limited by dropping the number of rows specified in the <result offset clause> 
from the beginning of the result produced by the <query expression>. If the 
cardinality of the result of an evaluation of a <query expression> is less than
 the offset value specified by a <result offset clause>, then the derived table is empty.

And

<query expression> ::=
  [ <with clause> ] <query expression body>
      [ <order by clause> ] [ <result offset clause> ] [ <fetch first clause> ]

<result offset clause> ::=
  OFFSET <offset row count> { ROW | ROWS }

<fetch first clause> ::=
  FETCH { FIRST | NEXT } [ <fetch first quantity> ] { ROW | ROWS } { ONLY | WITH TIES }

<fetch first quantity> ::=
    <fetch first row count>
  | <fetch first percentage>

<offset row count> ::=
  <simple value specification>

<fetch first row count> ::=
  <simple value specification>

<fetch first percentage> ::=
  <simple value specification> PERCENT

[martint]

Do we want to support simplified syntax OFFSET n LIMIT m as well?

Yes, that would fall out naturally from having LIMIT be an alternate form of FETCH FIRST/NEXT.

Do we want to support LIMIT m OFFSET n version too. It is misleading […]

Agreed. That’s confusing. Let’s not add it for now. We can always expand later.

[arminmaurice1990]

https://cloud.google.com/bigquery/docs/reference/standard-sql/query-syntax As above, the syntax is almost fully interchangeable for non-trivial queries, save for the ordering of limit and offset (offset being part of the limit clause, same with Postgres syntax https://www.postgresql.org/docs/8.1/queries-limit.html which I know presto already translates to).

edit: seems as though this is standard with impala as well http://impala.apache.org/docs/build/html/topics/impala_offset.html