Does a utf8_unicode_cs collation exist?

Question

Does anyone know if a utf8_unicode_cs collation for MySQL exists? So far, my searches have come up dry. If it simply doesn\'t exist yet, is it fairly straight-forward to cre

Answer 1

I came across the same issue and after some Googling, it seems that MySQL doesn't include it. To "simulate it", as you put it,

1) To ensure case-sensitivity in the DB: set the table column to utf8_bin collation
This allows:

• strict SELECTs: SELECT "Joe" will NOT return rows with "joe" / "joE" / "jOe" / etc
• strict UNIQUE index: a column with a UNIQUE index will treat case differences as different values. For example, if a utf8_unicode_ci collation is used, inserting "Joe" on a table that already has "joe" will trigger a "Duplicate key" error. If ut8_bin is used, inserting "Joe" will work fine.

2) To get the proper ordering in results: add the collation to the SQL query:

SELECT ... ORDER BY column COLLATE utf8_unicode_ci

Answer 2

This is an old question but does not seem to be superseded by any other, so I thought it worth posting that things have changed.

MySQL version 8 now has the following collations for utf8mb4:

 utf8mb4_0900_ai_ci 
 utf8mb4_0900_as_ci
 utf8mb4_0900_as_cs
 ... and many language-specific variants of same.

(no _ai_cs as far as I know, but that would in any case be less useful: few reasons to group [a] and [a-acute] and then separately group [A] and [A-acute]).

The purpose of the original question's hypothetical "utf8_unicode_cs" is fulfilled by utf8mb4_0900_as_cs. (The 0900 means it uses Unicode v 9.0.0 as opposed to 4.0.0 used by utf8_unicode_ci.)

To use these you'd need to change the field from utf8 to utf8mb4 character set - but that's a generally good idea anyway because the old 3-byte-max encoding can't handle e.g. emoji and other non-BMP characters.

Source: https://dev.mysql.com/doc/refman/8.0/en/charset-mysql.html