MySQL transform case-sensitive unique field into unique case-insensitive field - mysql

Question

This is an interesting challenge question as there can be multiple ways to solve this problem :)
I have an ID column that is unique but case-sensitive, ex:
----- ID ------
0018000001K6dkh -> record 1
0018000001K6dkH -> record 2 (different from record 1)
As MySQL is case insensitive in utf8, it is considering the two ID values as identical:
SELECT COUNT(*) FROM table WHERE id='0018000001K6dkh' //returns 2 instead of 1
SELECT COUNT(*) FROM table WHERE id='0018000001K6dkH' //returns 2 instead of 1
I need to build a MySQL function that I can apply to this column to transform all IDs into a case-insensitive and unique IDs, ex:
function('0018000001K6dkh') = something
function('0018000001K6dkH') = something different
function('0018000000ttzlB') = something even different
function('0018000000tTzlB') = something even more different
Note: I don't want to use collations, because I would have to change all the WHEREs and JOINs in my application (Laravel PHP). I want to change the IDs permanently.

Answer 1

According the official MySQL documentation you can set the collation on a per column basis (*see data_type section for CHAR, VARCHAR, TEXT, ENUM, and SET types).
This should change the default manner in which they are compared to string literals and each other, but I am not familiar with the rules used when comparing fields of differing collation with each other.

Answer 2

This is from mysql http://dev.mysql.com/doc/refman/5.7/en/case-sensitivity.html
To cause a case-sensitive comparison of nonbinary strings to be case
insensitive, use COLLATE to name a case-insensitive collation. The
strings in the following example normally are case sensitive, but
COLLATE changes the comparison to be case insensitive:
SET #s1 = 'MySQL' COLLATE latin1_bin;
SET #s2 = 'mysql' COLLATE latin1_bin;
SELECT #s1 = #s2;
return false
using #s1 COLLATE latin1_swedish_ci = #s2;
SELECT #s1 COLLATE latin1_swedish_ci = #s2;
return true
or use BINARY
SELECT COUNT(*) FROM table WHERE BINARY id='0018000001K6dkh'
SELECT COUNT(*) FROM table WHERE BINARY id='0018000001K6dkH'