Documentation on SELECT statements at http://www.sqlite.org/draft/lang_select.html has now been updated and amplified.
On Thu, Jan 30, 2014 at 5:52 AM, Zsbán Ambrus <amb...@math.bme.hu> wrote: > Hi! > > I'm writing to you about the syntax diagram that appears on > "http://sqlite.org/draft/lang_select.html";, and is a draft for the > next version of sqlite (3.8.3). I find this diagram confusing, and > would rather prefer to have something similar to > "http://sqlite.org/lang_select.html";, only of course updated to show > the syntax changes in 3.8.3. > > I have two concrete problems with this diagram. > > 1. It seems to imply that LIMIT clauses are attached to each part of a > compound select. For example, in a select statement like this: > > SELECT col1 FROM tbl1 UNION ALL SELECT col2 FROM tbl2 ORDER BY 1 LIMIT > 5; > > does the LIMIT clause cause sqlite3 to limit the result of the whole > compound statement, or does it ask only to limit the tbl2 branch and > then take the union? The text of the page later appears to imply that > the LIMIT applies to the whole statement (correct me if I'm wrong > here), but the new syntax diagram really seems to show the opposite. > > 2. This diagram for select too big. The diagram in the released docs > is broken down to smaller parts, and I find that easier to read. > > In fact I don't like to read diagrams like this at all. I'd be > happier to read an alternate representation of the grammar without > images, using only a bnf-like text description. I'm not saying the > images should go away, only that a text representation should also be > available somewhere, possibly on a separate page like > "http://sqlite.org/draft/syntaxdiagrams.html"; if you don't want them > on the main pages. > > That said, there is at least one change I like in the new diagram. > Namely, the grammar rule single-source is renamed to > table-or-subquery, and I think the new name is clearer, so thank you > for that. > > Thank you for your work on improving sqlite3, > > Ambrus > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > -- D. Richard Hipp d...@sqlite.org _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
