Collation | BestHub

Aikesheng Open Source Community

Apr 1, 2025 · Databases

Resolving Column Length Expansion Errors in OceanBase: Charset and Collation Considerations

This article explains why altering a column length in OceanBase may trigger an "Alter charset or collation type not supported" error, analyzes the underlying charset and collation settings, and provides a solution that explicitly specifies charset and collation to ensure successful column expansion across versions.

CharsetCollationColumn Expansion

0 likes · 6 min read

Resolving Column Length Expansion Errors in OceanBase: Charset and Collation Considerations

IT Services Circle

Nov 11, 2024 · Databases

Handling Case Sensitivity in MySQL Brand Table to Prevent Duplicate Entries

This article examines why a MySQL table with a case‑insensitive collation returns uppercase brand names when searching for lowercase input, analyzes the underlying charset and collation settings, and proposes backend pagination with a case‑insensitive fuzzy search and a unique index to reliably prevent duplicate brand records.

Case InsensitivityCollationDatabase Design

0 likes · 8 min read

Aikesheng Open Source Community

Jun 24, 2024 · Databases

Resolving Illegal Mix of Collations Error After Upgrading MySQL 5.7 to 8.0

This article explains why upgrading MySQL from 5.7 to 8.0 can cause an "Illegal mix of collations" error in FIND_IN_SET queries, analyzes the root cause, and presents three practical solutions—adjusting server parameters, altering table collations, or rewriting the SQL—to restore correct operation.

CollationDatabaseMySQL

0 likes · 10 min read

Resolving Illegal Mix of Collations Error After Upgrading MySQL 5.7 to 8.0

Tencent Database Technology

May 31, 2023 · Databases

MySQL Character Set Implementation: From System Tables to Source Code

This article explores MySQL character set implementation by analyzing system tables (CHARACTER_SETS and COLLATIONS) in information_schema and tracing internal source code structures like CHARSET_INFO, initialization logic, and client connection handling.

Client-Server ProtocolCollationDatabase Internals

0 likes · 6 min read

MySQL Character Set Implementation: From System Tables to Source Code

Aikesheng Open Source Community

Feb 7, 2023 · Databases

Resolving Illegal Mix of Collations Errors in MySQL 8.0 Views

This article analyzes why MySQL 8.0 reports an illegal mix of collations when querying a view that joins tables with different character sets, demonstrates reproducing the issue, explains the role of the CONVERT function and default collation variables, and provides practical recommendations to avoid such errors.

CollationConvert FunctionDatabase Administration

0 likes · 9 min read

Resolving Illegal Mix of Collations Errors in MySQL 8.0 Views

Aikesheng Open Source Community

Oct 17, 2022 · Databases

Understanding MySQL Collation and Character Set: Effects on Data Retrieval and Storage

This article explains MySQL collations and character sets, shows how to view and set them, and demonstrates through test cases that while data insertion is unaffected by collation, query results are influenced by the collation defined on columns or the connection.

CollationDatabaseMySQL

0 likes · 6 min read

Understanding MySQL Collation and Character Set: Effects on Data Retrieval and Storage

Aikesheng Open Source Community

Mar 24, 2022 · Databases

Understanding MySQL Character Sets, Collations, and Common Encoding Issues

This article explains MySQL's various character sets and collations, describes important system variables such as character_set_client and character_set_connection, demonstrates how to query supported encodings, and provides practical examples for avoiding and fixing garbled text caused by mismatched encodings.

CollationMySQLSQL

0 likes · 10 min read

Understanding MySQL Character Sets, Collations, and Common Encoding Issues

Aikesheng Open Source Community

Jul 8, 2020 · Databases

Understanding Character Sets in MySQL: Databases, Tables, and Columns

This article explains how to specify and manage character sets and collations when creating or altering MySQL databases, tables, views, triggers, and columns, illustrating the impact on stored procedures and data retrieval with practical SQL examples.

CollationDatabaseMySQL

0 likes · 11 min read

Understanding Character Sets in MySQL: Databases, Tables, and Columns

Aikesheng Open Source Community

Jun 24, 2020 · Databases

Using Character Set Introducer, Conversion Functions, and Collation in MySQL

This article explains how to explicitly specify character sets and collations in MySQL using the character introducer, CONVERT and CHARSET functions, SET NAMES/SET CHARACTER SET statements, and the COLLATE clause, with practical examples and guidance on coercibility.

CollationConvert FunctionIntroducer

0 likes · 9 min read

Using Character Set Introducer, Conversion Functions, and Collation in MySQL

Aikesheng Open Source Community

Jun 10, 2020 · Databases

MySQL Character Sets and Collations: Concepts, Usage, and Migration

This article explains MySQL character sets and collations, describes common character sets such as latin1, utf8mb3, utf8mb4 and gb18030, shows how to query available sets and collations, compares PAD SPACE and NO PAD behavior, and provides step‑by‑step migration examples between utf8, utf8mb3 and utf8mb4.

CollationMySQLcharacter set

0 likes · 12 min read

MySQL Character Sets and Collations: Concepts, Usage, and Migration

Aikesheng Open Source Community

Apr 22, 2020 · Databases

Why Does the Same SQL Run Fast on MariaDB but Slow on MySQL 5.7?

A production database migration from MariaDB 10.4 to MySQL 5.7 caused a previously fast SQL query to become extremely slow due to differing column collations that prevented index usage, and the article explains how to diagnose the issue and resolve it by aligning collations or using explicit conversion.

CollationDatabase OptimizationIndex

0 likes · 3 min read

Why Does the Same SQL Run Fast on MariaDB but Slow on MySQL 5.7?

Aikesheng Open Source Community

Aug 7, 2019 · Databases

Performance Impact of Charset and Collation Settings on MySQL 5.7 vs 8.0

A sysbench benchmark comparing MySQL 5.7.25 and MySQL 8.0.15 shows that latin1 charset favors 5.7, while utf8mb4 dramatically improves 8.0 performance, and that collations such as utf8mb4_unicode_ci can further affect query speed.

CharsetCollationDatabase Benchmark

0 likes · 4 min read

Performance Impact of Charset and Collation Settings on MySQL 5.7 vs 8.0

Aikesheng Open Source Community

Mar 28, 2019 · Databases

Understanding MySQL Character Set Parameters and Troubleshooting Encoding Issues

This article explains MySQL's character set and collation variables, illustrates how they interact during data import, analyzes a failure caused by mismatched charset settings, and provides guidance on proper configuration and troubleshooting of encoding problems.

CollationDatabaseMySQL

0 likes · 7 min read

Understanding MySQL Character Set Parameters and Troubleshooting Encoding Issues

360 Quality & Efficiency

Mar 26, 2018 · Databases

Handling Case Sensitivity in MySQL: Collation, Data Types, and Query Solutions

This article explains why MySQL queries can become case‑insensitive, describes how collations and character sets control case sensitivity, and presents three practical solutions—changing the collation, converting column types, and using binary or collate clauses in queries—to achieve case‑sensitive behavior.

CharsetCollationDatabase

0 likes · 5 min read

Handling Case Sensitivity in MySQL: Collation, Data Types, and Query Solutions