Re: text -> time cast problem

[2001-12-04 18:15] Tom Lane said:
| Peter Eisentraut <peter_e(at)gmx(dot)net> writes:
| > That appears to be what it does, but it's not correct. I point you to
| > SQL92:
|
| > 16)The data type of a <time literal> that does not specify <time
| > zone interval> is TIME(P), where P is the number of digits in
| > <seconds fraction>, if specified, and 0 otherwise. The data
| > type of a <time literal> that specifies <time zone interval>
| > is TIME(P) WITH TIME ZONE, where P is the number of digits in
| > <seconds fraction>, if specified, and 0 otherwise.
|
| > In this "time literal" context, TIME does not take a precision value at
| > all. The new code certainly has this wrong.

The current handling of <time literal> and <timestamp literal> appear
to be correct from my reading of the sql standards.

| But you are definitely right that
|
| time '17:12:28.123'

sql-99 seems to contradict this assertion.
page 160 (Syntax Rules, 6.1 <data type>)

30) If <time precision> is not specified, then 0 (zero) is implicit.
If <timestamp precision> is not specified, then 6 is implicit.

meaning (to me) that "TIME" should be equivalent "TIME(0)".

[snip]

| in general we'd like TYPE 'LIT' and 'LIT'::TYPE to
| produce the same answers.

I agree wholly with this statement.

[snip]

To get back to my original problem report...

I believe the proper solution would be to update the documentation
to reflect the fact that "TIME 'hh:mm:ss.ff'" will correctly drop
the '.ff' seconds fraction.

That said, how should "time"('hh:mm:ss.ff') behave? How could
<time precision> be specified in this syntax? If there is no way
to specify <time precision>, I believe we should drop the seconds
fraction from <time string>. Is there any reason we couldn't drop
this typename-as-a-function-call syntax for types like "time" and
"timestamp"?

cheers.
brent

p.s. sorry for not replying sooner...

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