On Dec 4, 2007, at 10:35 PM, Joe Wilson wrote:
--- Dan <[EMAIL PROTECTED]> wrote:
i.e., if we have:
CREATE TABLE x1(a, b, c);
CREATE TABLE x2(a, b, c);
then the following pairs of statements are equivalent:
...
SELECT x1.b, a FROM x1 UNION SELECT a, b FROM x2 ORDER BY b;
SELECT x1.b, a FROM x1 UNION SELECT a, b FROM x2 ORDER BY 2;
Don't you mean ORDER BY 1?
I'm talking about sqlite cvs, as the code is implemented right
now (see matchOrderbyToColumn() in select.c). So 2 is correct,
as the test you did shows.
The "b" in the ORDER BY does not match "x1.b" because it is
not a simple identifier (according to matchOrderbyToColumn()).
It does not match either "<identifier>" or "<expr> as <identifier>".
After failing to find a match for "b" in the leftmost SELECT,
SQLite searches the next leftmost and matches "b" to "b"
(column 2).
That's how it is at the moment, anyhow.
http://www.mail-archive.com/sqlite-users@sqlite.org/msg23985.html
Cheers. I'm starting to realise why this little corner of sqlite
is the way it is...
Dan.
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