How many Chinese characters can be displayed when the length of varchar type in MySQL is set to 30
In MySQL, when the length of the VARCHAR type is set to 30, the number of Chinese characters it can store depends on the encoding method of the character set. Common character set encodings are UTF-8 and UTF-16, of which UTF-8 is the most commonly used.
Under the UTF-8 character set, each Chinese character occupies 3 bytes. Therefore, the number of Chinese characters that VARCHAR(30) can store will be 30 / 3 = 10 Chinese characters.
Note that the length calculation here assumes that each character is a Chinese character. If the name contains other non-Chinese characters (such as English letters, numbers, etc.), it will occupy fewer bytes, because English letters and numbers only occupy 1 byte under UTF-8 encoding.
If you need to store more Chinese characters or characters, please increase the length of the VARCHAR field accordingly.
How many characters are needed to represent Chinese characters in different encodings
The number of bytes occupied by Chinese characters in different character encodings is different. The following is the number of bytes required to represent Chinese characters in common character encodings (UTF-8, UTF-16, UTF-32):
UTF-8 encoding:
Each Chinese character occupies 3 bytes.
UTF-16 encoding:
Each Chinese character occupies 2 bytes.
UTF-32 encoding:
Each Chinese character occupies 4 bytes.
These encoding methods are the implementations of the Unicode character set, among which UTF-8 is the most commonly used encoding method, because it can effectively compress ASCII characters, save storage space, and supports a range that includes all Unicode characters.
It should be noted that when storing or transmitting Chinese characters, it is necessary to ensure that a consistent character encoding is used to avoid problems such as garbled characters or character truncation. Most modern applications and databases use UTF-8 encoding because it provides a wide range of character support and is the preferred encoding for internationalization.