Re: Intervals and ISO 8601 duration

On 2023-01-13 17:07:17 -0700, Martin L. Buchanan wrote:
> Just tried casting interval to bytea to see the binary layout, but that direct
> cast is not allowed.

A cast generally doesn't just reinterpret the same bit pattern as a
different type, it converts the value.

For example, in C (to choose a language "closer to the metal" than
SQL), «int a = 3; float f = (float)a;» assigns 3.0 to f, not 4.2E-45
(which would be 0x0000_0003 interpreted as an IEEE-754 single precision
FP value).

So there's no guarantee that a cast to bytea would have done what you
expected even if it existed.

Oracle has a function which returns the internal representation of a
value as a series of (decimal) byte values. Back in the days when I was
new to Oracle I used this to figure out how Oracle stores NUMBER, but
now I've forgotten the name of the function. Maybe adding something like
this to PostgreSQL would be worthwhile?

hp

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_ | Peter J. Holzer | Story must make more sense than reality.
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