issue_comments

Wrote about this in the annotated release notes for 0.58: https://simonwillison.net/2021/Jul/16/datasette-058/

Started a conversation about this on the SQLite forum: https://sqlite.org/forum/forumpost/2d76f2bcf65d256a?t=h

I wrote this code: ```python _order_by_re = re.compile(r"(^.) order by [a-zA-Z_][a-zA-Z0-9_]+( desc)?$", re.DOTALL) _order_by_braces_re = re.compile(r"(^.) order by [[^]]+]( desc)?$", re.DOTALL)

def strip_order_by(sql): for regex in (_order_by_re, _order_by_braces_re): match = regex.match(sql) if match is not None: return match.group(1) return sql

@pytest.mark.parametrize( "sql,expected", [ ("blah", "blah"), ("select * from foo", "select * from foo"), ("select * from foo order by bah", "select * from foo"), ("select * from foo order by bah desc", "select * from foo"), ("select * from foo order by [select]", "select * from foo"), ("select * from foo order by [select] desc", "select * from foo"), ], ) def test_strip_order_by(sql, expected): assert strip_order_by(sql) == expected ``` But it turns out I don't need it! The SQL that is passed to the facet class is created by this code: https://github.com/simonw/datasette/blob/ba11ef27edd6981eeb26d7ecf5aa236707f5f8ce/datasette/views/table.py#L677-L684

And the only place that uses that sql_no_limit variable is here: https://github.com/simonw/datasette/blob/ba11ef27edd6981eeb26d7ecf5aa236707f5f8ce/datasette/views/table.py#L733-L745

So I can change that to sql_no_limit_no_order and fix the bug that way instead.

The challenge here is that faceting doesn't currently modify the inner SQL at all - it wraps it so that it can work against any SQL statement (though Datasette itself does not yet take advantage of that ability, only offering faceting on table pages).

So just removing the order by wouldn't be appropriate if the inner query looked something like this:

sql select * from items order by created desc limit 100 Since the intent there would be to return facet counts against only the most recent 100 items.

In SQLite the limit has to come after the order by though, so the fix here could be as easy as using a regular expression to identify queries that end with order by COLUMN (desc)? and stripping off that clause.