Tag: null

Waiting for PostgreSQL 18 – Allow json{b}_strip_nulls to remove null array elements

On 5th of March 2025, Andrew Dunstan committed patch:

Allow json{b}_strip_nulls to remove null array elements
 
An additional paramater ("strip_in_arrays") is added to these functions.
It defaults to false. If true, then null array elements are removed as
well as null valued object fields. JSON that just consists of a single
null is not affected.
 
Author: Florents Tselai <florents.tselai@gmail.com>
 
Discussion: https://postgr.es/m/4BCECCD5-4F40-4313-9E98-9E16BEB0B01D@gmail.com

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Waiting for PostgreSQL 15 – Add UNIQUE null treatment option

On 3rd of February 2022, Peter Eisentraut committed patch:

Add UNIQUE null treatment option 
 
The SQL standard has been ambiguous about whether null values in
unique constraints should be considered equal or not.  Different
implementations have different behaviors.  In the SQL:202x draft, this
has been formalized by making this implementation-defined and adding
an option on unique constraint definitions UNIQUE [ NULLS [NOT]
DISTINCT ] to choose a behavior explicitly.
 
This patch adds this option to PostgreSQL.  The default behavior
remains UNIQUE NULLS DISTINCT.  Making this happen in the btree code
is pretty easy; most of the patch is just to carry the flag around to
all the places that need it.
 
The CREATE UNIQUE INDEX syntax extension is not from the standard,
it's my own invention.
 
I named all the internal flags, catalog columns, etc. in the negative
("nulls not distinct") so that the default PostgreSQL behavior is the
default if the flag is false.
 
Reviewed-by: Maxim Orlov <orlovmg@gmail.com>
Reviewed-by: Pavel Borisov <pashkin.elfe@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/84e5ee1b-387e-9a54-c326-9082674bde78@enterprisedb.com

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