On 24 June 2013 04:29, Josh Berkus j...@agliodbs.com wrote:
On 06/23/2013 08:00 PM, Andrew Gierth wrote:
OK, let's try to cover all the bases here in one go.
1. Stick with ?column? as a warning flag that you're not supposed to
be using this without aliasing it to something.
How do I actually supply an alias which covers both columns? What does
that look like, syntactically?
There are a number of possible syntaxes:
SELECT unnest, ?column? FROM unnest(ARRAY['x','y']) WITH ORDINALITY;
or
SELECT unnest.unnest, unnest.?column? FROM unnest(ARRAY['x','y'])
WITH ORDINALITY;
unnest | ?column?
+--
x |1
y |2
(2 rows)
SELECT t, ?column? FROM unnest(ARRAY['x','y']) WITH ORDINALITY AS t;
or
SELECT t.t, t.?column? FROM unnest(ARRAY['x','y']) WITH ORDINALITY AS t;
t | ?column?
---+--
x |1
y |2
(2 rows)
SELECT val, ?column? FROM unnest(ARRAY['x','y']) WITH ORDINALITY AS t(val);
or
SELECT t.val, t.?column? FROM unnest(ARRAY['x','y']) WITH ORDINALITY
AS t(val);
val | ?column?
-+--
x |1
y |2
(2 rows)
SELECT val, ord FROM unnest(ARRAY['x','y']) WITH ORDINALITY AS t(val, ord);
or
SELECT t.val, t.ord FROM unnest(ARRAY['x','y']) WITH ORDINALITY AS t(val, ord);
val | ord
-+-
x | 1
y | 2
(2 rows)
My suggestion was to replace ?column? with ordinality wherever it
appears above, for the user's convenience, but so far more people
prefer ?column? as a way of indicating that you're supposed to
provide an alias for the column.
If that's what people prefer, I don't mind --- it's still going to be
a very handy new feature.
Regards,
Dean
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