MySQL distinction between e and é (e acute) – UNIQUE index

by

and collation is “utf8_general_ci”.

And that’s the answer. If you’re using utf8_general_ci (actually it applies to all utf_..._[ci|cs]) collation then diacritics are bypassed in comarison, thus:

SELECT "e" = "é" AND "O" = "Ó" AND "ä" = "a"

Results in 1. Indexes also use collation.

If you want to distinguish between ą and a then use utf8_bin collation (keep in mind that it also distinguish between uppercase and lowercase characters).

By the way name and age don’t guarantee any uniqueness.

More Related Contents:

  1. How to convert an entire MySQL database characterset and collation to UTF-8?
  2. Change MySQL default character set to UTF-8 in my.cnf?
  3. How do I add indexes to MySQL tables?
  4. Differences between INDEX, PRIMARY, UNIQUE, FULLTEXT in MySQL?
  5. How can I find non-ASCII characters in MySQL?
  6. When should I use a composite index?
  7. Is the primary key automatically indexed in MySQL?
  8. MySQL indexes – what are the best practices?
  9. How to see indexes for a database or table in MySQL?
  10. How do I add a custom CHECK constraint on a MySQL table?
  11. What are the differences between utf8_general_ci and utf8_unicode_ci? [duplicate]
  12. Speeding up row counting in MySQL
  13. How to detect UTF-8 characters in a Latin1 encoded column – MySQL
  14. How to add not null constraint to existing column in MySQL
  15. DOs and DONTs for Indexes [closed]
  16. Fetching UTF-8 text from MySQL in R returns “????”
  17. MySQL performance: multiple tables vs. index on single table and partitions
  18. Is there any performance gain in indexing a boolean field?
  19. Does Order of Fields of Multi-Column Index in MySQL Matter
  20. Create an index on a huge MySQL production table without table locking
  21. How to change the default charset of a MySQL table?
  22. MySQL Integer vs DateTime index
  23. MySQL optimizing INSERT speed being slowed down because of indices
  24. Would it help to add index to BIGINT column in MySQL?
  25. MySQL – why not index every field?
  26. List of Constraints from MySQL Database
  27. MySQL: how to index an “OR” clause
  28. Workaround in mysql for partial Index or filtered Index?
  29. How to do unique constraint works with NULL value in MySQL
  30. ERROR 1115 (42000): Unknown character set: ‘utf8mb4’

Leave a Comment