MID function parses a source string to return a sub-string that
begins at a specified position and contains at most the specified
number of characters. The first parameter to the function is
the source string from which the sub-string is extracted. The second
and third parameters are optional and specify the start and end
position within the source string from which the sub-string is to
be extracted. The first character in the source string is at position
0. The default starting position is 0 if not provided. If the number
of characters to return is not provided, the default is the remaining length
of the source string after the start position.
String [, Start Position [, Max Length]])
- Source String Required string parameter; contains the source string from which
the sub-string will be extracted.
- Start Position Optional integral number parameter; contains the zero-based
position of the first character within Source String for
the sub-string to be extracted. If this parameter is not provided,
the default start position is 0 and the entire Source String value
will be returned.
- Max Length Optional integral number parameter; contains the maximum number
of characters to return from Source String after Start
Position. If this parameter is not provided, all characters
after Start Position will be returned as the sub-string.