What should I do if garbled characters appear when querying in php?

PHP is a widely used programming language commonly used for web development. When using PHP to perform database queries, sometimes there will be problems with processing garbled characters. This problem usually occurs when dealing with Chinese characters.

The character encoding stored in the database may be different from the character encoding of the web page, which may cause garbled characters when querying. While this issue may seem simple, it can have a negative impact on your website's performance and security.

The following are several methods to solve the problem of garbled characters when querying in PHP.

1. Set the database character encoding to UTF-8

UTF-8 is a character encoding that can support all Unicode characters. If the database uses UTF-8 encoding, there will be no garbled characters when querying. Therefore, setting the database character encoding to UTF-8 is a way to solve the garbled problem.

You can use the following code to set the character encoding of the MySQL database to UTF-8:

$conn = mysqli_connect($servername, $username, $password, $dbname);
mysqli_set_charset($conn, "utf8");

Among them, $servername is the database server name, $username is the database username, and $password is the database password. , $dbname is the database name. The mysqli_set_charset() function is used to set the character set.

2. Set the character encoding before querying

Setting the correct character encoding before querying can also solve the problem of garbled characters. You can use the following PHP code to set the character encoding:

$conn = mysqli_connect($servername, $username, $password, $dbname);
mysqli_query($conn, "SET NAMES 'utf8'");

where $servername, $username, $password and $dbname are the database server name, user name, password and database name respectively. The mysqli_query() function sets the character encoding to UTF-8.

3. Use the PHP iconv() function for character encoding conversion

The PHP iconv() function can convert one character encoding to another character encoding. You can use the iconv() function to convert query results from the database character set to the web page character set. The following is an example:

$conn = mysqli_connect($servername, $username, $password, $dbname);
mysqli_set_charset($conn, "utf8");
$result = mysqli_query($conn, "SELECT * FROM `user`");
while ($row = mysqli_fetch_array($result)) {
    $name = iconv("UTF-8", "GB2312//IGNORE", $row['name']);
    echo $name . "
";
}

In this example, the name field in the query result is converted from UTF-8 encoding to GB2312 encoding. Use the //IGNORE parameter to ignore characters that cannot be converted.

4. Use the PHP mb_convert_encoding() function to convert character encodings

The PHP mb_convert_encoding() function can also convert character encodings to other encodings. The following is an example:

$conn = mysqli_connect($servername, $username, $password, $dbname);
mysqli_set_charset($conn, "utf8");
$result = mysqli_query($conn, "SELECT * FROM `user`");
while ($row = mysqli_fetch_array($result)) {
    $name = mb_convert_encoding($row['name'], "GBK", "UTF-8");
    echo $name . "
";
}

In this example, the name field in the query result is converted from UTF-8 encoding to GBK encoding.

Summary

The above method can solve the problem of garbled characters when querying in PHP. When using PHP for database query, it is recommended to set the database character encoding to UTF-8 and set the correct character encoding before querying. If you still have garbled characters, you can use the PHP iconv() function or the PHP mb_convert_encoding() function to convert character encodings.

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