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MySQL 8.4 Reference Manual  /  Character Sets, Collations, Unicode

Chapter 12 Character Sets, Collations, Unicode

Table of Contents

12.1 Character Sets and Collations in General
12.2 Character Sets and Collations in MySQL
12.2.1 Character Set Repertoire
12.2.2 UTF-8 for Metadata
12.3 Specifying Character Sets and Collations
12.3.1 Collation Naming Conventions
12.3.2 Server Character Set and Collation
12.3.3 Database Character Set and Collation
12.3.4 Table Character Set and Collation
12.3.5 Column Character Set and Collation
12.3.6 Character String Literal Character Set and Collation
12.3.7 The National Character Set
12.3.8 Character Set Introducers
12.3.9 Examples of Character Set and Collation Assignment
12.3.10 Compatibility with Other DBMSs
12.4 Connection Character Sets and Collations
12.5 Configuring Application Character Set and Collation
12.6 Error Message Character Set
12.7 Column Character Set Conversion
12.8 Collation Issues
12.8.1 Using COLLATE in SQL Statements
12.8.2 COLLATE Clause Precedence
12.8.3 Character Set and Collation Compatibility
12.8.4 Collation Coercibility in Expressions
12.8.5 The binary Collation Compared to _bin Collations
12.8.6 Examples of the Effect of Collation
12.8.7 Using Collation in INFORMATION_SCHEMA Searches
12.9 Unicode Support
12.9.1 The utf8mb4 Character Set (4-Byte UTF-8 Unicode Encoding)
12.9.2 The utf8mb3 Character Set (3-Byte UTF-8 Unicode Encoding)
12.9.3 The utf8 Character Set (Deprecated alias for utf8mb3)
12.9.4 The ucs2 Character Set (UCS-2 Unicode Encoding)
12.9.5 The utf16 Character Set (UTF-16 Unicode Encoding)
12.9.6 The utf16le Character Set (UTF-16LE Unicode Encoding)
12.9.7 The utf32 Character Set (UTF-32 Unicode Encoding)
12.9.8 Converting Between 3-Byte and 4-Byte Unicode Character Sets
12.10 Supported Character Sets and Collations
12.10.1 Unicode Character Sets
12.10.2 West European Character Sets
12.10.3 Central European Character Sets
12.10.4 South European and Middle East Character Sets
12.10.5 Baltic Character Sets
12.10.6 Cyrillic Character Sets
12.10.7 Asian Character Sets
12.10.8 The Binary Character Set
12.11 Restrictions on Character Sets
12.12 Setting the Error Message Language
12.13 Adding a Character Set
12.13.1 Character Definition Arrays
12.13.2 String Collating Support for Complex Character Sets
12.13.3 Multi-Byte Character Support for Complex Character Sets
12.14 Adding a Collation to a Character Set
12.14.1 Collation Implementation Types
12.14.2 Choosing a Collation ID
12.14.3 Adding a Simple Collation to an 8-Bit Character Set
12.14.4 Adding a UCA Collation to a Unicode Character Set
12.15 Character Set Configuration
12.16 MySQL Server Locale Support

MySQL includes character set support that enables you to store data using a variety of character sets and perform comparisons according to a variety of collations. The default MySQL server character set and collation are utf8mb4 and utf8mb4_0900_ai_ci, but you can specify character sets at the server, database, table, column, and string literal levels. To maximize interoperability and future-proofing of your data and applications, we recommend that you use the utf8mb4 character set whenever possible.

Note

UTF8 is a deprecated synonym for utf8mb3, and you should expect it to be removed in a future version of MySQL. Specify utfmb3 or (preferably) utfmb4 instead.

This chapter discusses the following topics:

  • What are character sets and collations?

  • The multiple-level default system for character set assignment.

  • Syntax for specifying character sets and collations.

  • Affected functions and operations.

  • Unicode support.

  • The character sets and collations that are available, with notes.

  • Selecting the language for error messages.

  • Selecting the locale for day and month names.

Character set issues affect not only data storage, but also communication between client programs and the MySQL server. If you want the client program to communicate with the server using a character set different from the default, you need to indicate which one. For example, to use the latin1 Unicode character set, issue this statement after connecting to the server:

SET NAMES 'latin1';

For more information about configuring character sets for application use and character set-related issues in client/server communication, see Section 12.5, “Configuring Application Character Set and Collation”, and Section 12.4, “Connection Character Sets and Collations”.