LENGTH function
The LENGTH function is used for string manipulation on all string data types (BIT, BLOB, and CHARACTER) and returns an integer value giving the number of singletons in source_string.
Syntax
It If the source_string is NULL, the result is the NULL value. The term singleton refers to a single part (BIT, BYTE, or CHARACTER) within a string of that type.
For example:
LENGTH('Hello World!');LENGTH('');