Error
Error Code:
3148
MySQL Error 3148: Invalid JSON Path Encoding
Description
This error occurs when MySQL encounters a JSON path expression that is not encoded in the expected UTF-8 character set. It indicates a mismatch between the required 'utf8' encoding and the actual character set used for the provided path expression, preventing the database from correctly processing the JSON operation.
Error Message
A path expression must be encoded in the utf8 character set. The path expression '%s' is encoded in character set '%s'.
Known Causes
4 known causesClient Character Set Mismatch
The application connecting to MySQL is configured to use a character set other than UTF-8 when sending JSON path expressions to the server.
Explicit Non-UTF8 Path String
The JSON path expression string is hardcoded or programmatically generated within the application using an encoding other than UTF-8.
Database/Column Encoding Discrepancy
While less common for the path itself, a broader character set misalignment at the database, table, or column level can sometimes contribute to encoding issues.
System Locale Interference
The operating system's locale or environment settings might influence the default character encoding used by applications, leading to non-UTF8 path expressions.
Solutions
3 solutions available1. Ensure UTF-8 Encoding for JSON Path Expressions easy
Verify that the JSON path strings used in your queries are explicitly encoded in UTF-8.
1
When constructing your JSON path expressions, ensure that any special characters or non-ASCII characters are properly represented using UTF-8 encoding. If you are dynamically generating these paths, confirm that the generation process uses UTF-8.
2
If the path is a literal string in your SQL query, ensure your SQL client or application is sending it to the MySQL server using UTF-8. This is typically handled by setting the client character set.
SET NAMES 'utf8mb4';3
In your application code (e.g., Python, Java, PHP), when preparing SQL statements that include JSON path expressions, ensure that the connection to the MySQL database is configured to use UTF-8 (preferably `utf8mb4` for full Unicode support).
2. Convert Non-UTF-8 Path Strings to UTF-8 medium
Explicitly convert any identified non-UTF-8 encoded path strings to UTF-8 before using them in MySQL.
1
Identify the specific query or operation that is causing the error and the problematic JSON path string. The error message '%s' will indicate the problematic path.
2
If the path is coming from an external source or an older system, you might need to use a conversion function in your application logic. For example, in Python, if you have a string `path_str` that is not UTF-8:
from imp import reload
import sys
reload(sys)
sys.setdefaultencoding('utf8')
# Assuming path_str is the problematic string
utf8_path_str = path_str.encode('utf-8', errors='replace').decode('utf-8')
# Use utf8_path_str in your MySQL query3
If the path is stored in another column within MySQL and you're trying to use it, you might need to convert it. However, it's generally better to fix the data source. If you must, consider a temporary solution:
SELECT JSON_EXTRACT(json_column, CONVERT(problematic_path_column USING utf8mb4)) FROM your_table;3. Configure MySQL Server and Client Character Sets medium
Ensure both the MySQL server and the client connection are set to use UTF-8 for consistent character handling.
1
Check the MySQL server's default character set and collation. Ideally, they should be `utf8mb4` and `utf8mb4_unicode_ci` respectively.
SHOW VARIABLES LIKE 'character_set_server';
SHOW VARIABLES LIKE 'collation_server';2
If the server defaults are not UTF-8, you can change them in the MySQL configuration file (`my.cnf` or `my.ini`). This requires a server restart.
[mysqld]
character-set-server=utf8mb4
collation-server=utf8mb4_unicode_ci3
For each client connection, ensure the character set is set to UTF-8. You can do this when establishing the connection in your application or by running `SET NAMES 'utf8mb4';` after connecting.
SET NAMES 'utf8mb4';4
If you are using a MySQL client tool (like MySQL Workbench, DBeaver), check its connection settings and ensure it's configured to use UTF-8 for the connection character set.