Optionally allow for queries to start with FROM, instead of with SELECT

[Mytherin]

The following SQL queries are now valid:

-- SELECT clause is optional, SELECT * is implied (if not included)
FROM tbl;

-- first 5 rows of the table
FROM tbl LIMIT 5;

-- select comes right after the from, after that the query follows the usual order
FROM tbl SELECT SUM(col) GROUP BY grp;

[domoritz]

In the last query, what happens with grp in the select? Is it implicit?

[Mytherin]

Ah no, it is equivalent to the query with SELECT in the front. You don’t need to mention all groups in the SELECT (although not doing so is nearly always a mistake, as it was here :))

[djouallah]

got an error here
From'lineitem' sum(L_quantity) group by l_shipmode;
BinderException: Binder Error: column "L_quantity" must appear in the GROUP BY clause or be used in an aggregate function

[Mytherin]

You are missing a SELECT:

From'lineitem' SELECT sum(L_quantity) group by l_shipmode;

Strangely enough, your query still passes our parser. It is equivalent to the following:

SELECT * FROM 'lineitem' AS sum(l_quantity) GROUP BY l_shipmode;

i.e. the sum is turned into a table alias.

[djouallah]

sorry, don't shoot at me :), can we get rid of select :)

[Mytherin]

That doesn't work because of ambiguities in the grammar (as your own query demonstrated).