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* Combining array slicing and indexing causes incorrect/confusing results
@ 2025-01-21 16:35 Jelte Fennema-Nio <me@jeltef.nl>
2025-01-21 17:04 ` Re: Combining array slicing and indexing causes incorrect/confusing results Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 1 reply; 2+ messages in thread
From: Jelte Fennema-Nio @ 2025-01-21 16:35 UTC (permalink / raw)
To: pgsql-bugs@lists.postgresql.org
Due to the way SubscriptingRef works there's no way for it to describe
a subscript sequence that both does a slice and a regular index in the
same SubscriptingRef. This results into weird behaviour like the
following:
> select ('{1, 2, 3, 4}'::int[])[1:4][2];
int4
──────
{}
(1 row)
It's possible to get the expected result by adding some additional parenthesis
> select (('{1, 2, 3, 4}'::int[])[1:4])[2];
int4
──────
2
(1 row)
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: Combining array slicing and indexing causes incorrect/confusing results
2025-01-21 16:35 Combining array slicing and indexing causes incorrect/confusing results Jelte Fennema-Nio <me@jeltef.nl>
@ 2025-01-21 17:04 ` Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 0 replies; 2+ messages in thread
From: Tom Lane @ 2025-01-21 17:04 UTC (permalink / raw)
To: Jelte Fennema-Nio <me@jeltef.nl>; +Cc: pgsql-bugs@lists.postgresql.org
Jelte Fennema-Nio <me@jeltef.nl> writes:
> Due to the way SubscriptingRef works there's no way for it to describe
> a subscript sequence that both does a slice and a regular index in the
> same SubscriptingRef.
Well, yeah, because they're fundamentally different operations.
A slice produces a value of the array type, a regular index
operation produces a value of the element type. So if you
mix the notations we assume you really meant slicing in each
subscript.
regards, tom lane
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2025-01-21 16:35 Combining array slicing and indexing causes incorrect/confusing results Jelte Fennema-Nio <me@jeltef.nl>
2025-01-21 17:04 ` Tom Lane <tgl@sss.pgh.pa.us>
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