The CHAR data type provides a performance boost because the database knows exactly how big every CHAR column will be and can make certain performance optimizations when reading or writing the data.

CHAR数据类型有助于性能提高，因为数据库确切地知道每个char列有多大，所以在读写数据时就可以执行某种性能优化。

youdao

The unsigned char data type, and byte data type will yield incorrect results and act as though they are signed types i. e. type char.

无符号字符数据类型和二进制数据类型将产生错误的计算结果，会当成有符号的数据类型进行计算。

youdao

String is actually not a data type in C. It actually is something called a char star and we'll come back to this before long.

字符串在C语言里其实不是一种数据类型,而是一种称为char，*的数据类型,这个知识点我以后会讲到。

哈佛公开课 - 计算机科学课程节选

We did it for silly purposes just to see how big each data type was, but on most systems the size of a char is what?

只是为了很傻的目的,来看看每个数据类型多大，但是在大多数的系统中char的大小是多少呢？

哈佛公开课 - 计算机科学课程节选