Command Reference : String and Date Function Reference
Syntax: @mid(str, n1[, n2])
Argument 1: string, str
Argument 2: integer, n1
Argument 3: integer, n2
Return: string
Returns n2 characters from str, starting at location n1 and continuing for n2 characters to the right. If you omit n2, it will return all of the remaining characters in the string.
%1 = @mid("I doubt it", 9, 2)
%2 = @mid("I doubt it", 9)
See also @left and @right.