CHAR_LENGTH

Syntax:
CHAR_LENGTH(str)

Returns the length of the string str, measured in characters. A
multibyte character counts as a single character. This means that for a
string containing five 2-byte characters, LENGTH() returns 10, whereas
CHAR_LENGTH() returns 5.

URL: https://dev.mysql.com/doc/refman/8.0/en/string-functions.html