In development, it is very common to encounter the problem of garbled characters when using MySQL. In this article, we will explore what causes garbled characters in MySQL and how to fix them.

1. Reasons for garbled characters

The reasons for garbled characters are usually related to the following three factors:

1.1 Character set mismatch

MySQL uses The character set may not match the character set used by your application. This often results in character conversion errors, resulting in garbled characters.

For example, if your application uses UTF-8 encoding, but the MySQL database uses Latin1 encoding, then when you get Latin1-encoded data from the database and try to display it in the application, you will A garbled code problem occurs.

1.2 Data storage errors

Sometimes, garbled characters may be caused by data storage errors. This usually occurs when inserting or updating data because MySQL attempts to convert the data to the specified character set. If an error occurs during the conversion process, the characters will be garbled.

For example, if you insert a string with non-ASCII characters into a Latin1 format table, it will cause data storage errors, resulting in garbled characters.

1.3 Client character set setting error

The character set setting of the MySQL connection client may be incorrect, resulting in garbled characters. This is usually caused by the client not having the character set options configured correctly.

2. Solution

To solve the problem of garbled characters in MySQL, you need to check the above three factors one by one and take corresponding solutions. Here are some common solutions:

2.1 Set the correct character set

Make sure that the MySQL database, table, and connecting client all use the same character set. The UTF-8 character set is recommended because it supports most languages and character sets.

You can set the MySQL character set in the following ways:

2.1.1 Set the character set parameters

Changecharacter_set_server,character_set_database,character_set_connection,character_set_resultsandcharacter_set_clientparameters are set to utf8mb4.

SET character_set_server = utf8mb4; SET character_set_database = utf8mb4; SET character_set_connection = utf8mb4; SET character_set_results = utf8mb4; SET character_set_client = utf8mb4;

2.1.2 Set the character set when creating the table

You can set the character set when creating the table:

CREATE TABLE example ( id INT NOT NULL, name VARCHAR(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci, email VARCHAR(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci, PRIMARY KEY (id) );

2.1.3 Modify the table character set

You can use the ALTER TABLE command to modify the table character set:

ALTER TABLE example CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;

2.2 Check whether the data is stored correctly

If the data is stored incorrectly, you can take the following measures:

2.2.1 Adjust Data Type

If your string with non-ASCII characters is stored as ASCII characters, a data storage error will occur. At this time, the data type needs to be changed to the correct type. For example, change VARCHAR to TEXT.

ALTER TABLE example MODIFY name TEXT CHARACTER SET utf8mb4;

2.2.2 Reinsert data

If the data has been stored incorrectly, you can delete the problematic record and reinsert the correct record. Make sure you set the correct character set options before reinserting.

2.3 Set the client character set

When connecting to the MySQL database, you can set the client character set. The following options can be added to the connection string:

jdbc:mysql://localhost:3306/example?useUnicode=true&characterEncoding=utf8

The above options will set the client character set to UTF-8.

3. Summary

This article introduces the causes of garbled MySQL characters and how to solve them. The solutions mainly include setting the correct character set, checking whether the data is stored correctly and setting the client character set. With clear solutions and practical tips, you can effectively solve any character garbled problem, thereby improving the stability and reliability of your application.

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