How to fix garbled characters in SQL query?

2 years ago
Benjamin Taylor
2 minutes

The situation of garbled characters mainly occurs because the encoding method of the database is not consistent with the encoding method of the application. You can try the following methods to solve the garbled character issue:

  1. Please confirm the encoding of the database. You can use SHOW VARIABLES LIKE ‘character\_set\_%’ to check the encoding of the database, paying special attention to the parameters character_set_client, character_set_connection, and character_set_results to ensure they match the encoding of the application.
  2. Change the encoding of the database. You can modify the database’s encoding using the ALTER DATABASE statement, for example ALTER DATABASE database_name CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;. Keep in mind that changing the database’s encoding will affect all existing tables and data, so please remember to backup your data before proceeding.
  3. Changing the encoding of a table. You can use the ALTER TABLE statement to change the encoding of a table, for example ALTER TABLE table_name CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;. Note that changing the table’s encoding will affect the data in that table.
  4. Change the encoding method of the connection. When connecting to the database, you can specify the encoding method in the connection string, such as jdbc:mysql://localhost:3306/database_name?useUnicode=true&characterEncoding=utf8mb4.
  5. Specify the encoding in the query statement. You can use the CONVERT function in the query statement to convert the query results to the specified encoding, for example SELECT CONVERT(column_name USING utf8mb4) FROM table_name;

In most cases, changing the encoding of the database and tables can solve the majority of garbled text issues. If the issue persists, check if the encoding used in the application matches the database, and ensure that the correct encoding is specified when connecting to the database.

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