so 14. 1. 2023 v 6:32 odesílatel Peter J. Holzer <hjp-pgsql@hjp.at> napsal:
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?
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