varchar php determines that the input does not exceed the length range of the varchar field of mysql

But if under utf-8 encoding, a Chinese character occupies 3 characters in length, such as the string $str = "Hello!!";
If you use the strlen function to judge, the length is 11, which is just longer than varchar length, but in fact this is not the case. If you directly execute the insert statement in phpmyadmin, this string can be inserted!
For the database, its length is 5, so how do we use PHP to get this length? Use the iconv_strlen() function!
echo iconv_strlen($str,'utf-8′);
Note that the second parameter is the current character set, so the results you get according to different character sets are calculated based on the length of one character!
The above statement will output 5. How about it? Can you judge it?

The above introduces how varchar PHP determines that the input does not exceed the length range of the varchar field of mysql, including the content of varchar. I hope it will be helpful to friends who are interested in PHP tutorials.