Inserting UTF-32 characters - sql

Question

I'm testing UTF-32 characters (specifically emojis) with SQL Server (2008 R2, 10.5) and at this stage I'm checking if the server supports the given code
For this case I'm using the :rose with the following query
SELECT '' + nchar(0x1F339) + 'test'
which returns back in Management Studio with (NULL).
What format do I need to encode the character to have it not return null in SQL Server

Answer 1

SQL Server only supports UCS-2, which is currently (almost) the same as UTF-16. So exactly 2 bytes per character and all that.

Answer 2

An idea, if I may. You can store the data in a BINARY or VARBINARY data field which doesn't care about encoding. You can then use a mapping table or external script to parse the binary into a text field replacing 0x1F339 with :rose: or your own custom forma for example.

Answer 3

Since it's UTF-32, it has two be written as two UTF-16 characters:
-- Returns: 🌹test
SELECT '' + nchar(0xD83C) + nchar(0xDF39) + 'test'
You can find this code under "UTF-16 Hex (C Syntax)" title, following your link.
Also I have to recommend this article, because it was very helpful during investigation: Unicode Escape Sequences Across Various Languages and Platforms (including Supplementary Characters)
Couple of options for those who are looking for answers:
SQL Server technically does not have character escape sequences, but
you can still create characters using either byte sequences or Code
Points using the CHAR() and NCHAR() functions. We are only concerned
with Unicode here, so we will only be using NCHAR().
All versions:
NCHAR(0 - 65535) for BMP Code Points (using an int/decimal value)
NCHAR(0x0 - 0xFFFF) for BMP Code Points (using a binary/hex value)
NCHAR(0 - 65535) + NCHAR(0 - 65535) for a Surrogate Pair / Two UTF-16
Code Units
NCHAR(0x0 - 0xFFFF) + NCHAR(0x0 - 0xFFFF) for a Surrogate Pair / Two
UTF-16 Code Units
CONVERT(NVARCHAR(size), 0xHHHH) for one or more characters in UTF-16
Little Endian (“HHHH” is 1 or more sets of 4 hex digits)
Starting in SQL Server 2012:
If database’s default collation supports Supplementary Characters
(collation name ends in _SC, or starting in SQL Server 2017 name
contains 140 but does not end in _BIN*, or starting in SQL Server
2019 name ends in _UTF8 but does not contain _BIN2), then NCHAR() can
be given Supplementary Character Code Points:
decimal value can go up to 1114111
hex value can go up to 0x10FFFF
Starting in SQL Server 2019:
“_UTF8” collations enable CHAR and VARCHAR data to use the UTF-8
encoding:
CONVERT(VARCHAR(size), 0xHH) for one or more characters in UTF-8 (“HH”
is 1 or more sets of 2 hex digits)
NOTE: The CHAR() function does not work for this purpose. It can only
produce a single byte, and UTF-8 is only a single byte for values 0 –
127 / 0x00 – 0x7F.