LEFT function
LEFT is a string manipulation function that returns a string consisting of the source string truncated to the LEFT given by the length expression.
Syntax
The source string can be of the CHARACTER, BLOB or BIT data type and the length must be of type INTEGER. The truncation discards the final characters of the source_string
The result is of the same type as the source string. If the length is negative or zero, a zero length string is returned. If either parameter is NULL, the result is NULL