How does Oracle calculate byte length?

In Oracle, you can use the LENGTHB function to calculate the byte length of a string, which will return the number of bytes occupied by the string.

Here is an example of using the LENGTHB function:

SELECT LENGTHB('你好') AS byte_length FROM dual;

In the example above, the string ‘你好’ contains two Chinese characters. After executing the SQL statement above, the number of bytes occupied by the string ‘你好’ will be returned. It is important to note that for different character sets and encoding methods, the same character may occupy a different number of bytes, so it is necessary to consider the impact of the character set and encoding method when calculating the byte length of a string.