char data type char

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。

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。