The standard Substring function is supported for extracting a portion of a string based on a position value and optional length. The SQL generated is SUBSTRING (expression FROM position FOR length). The expression to take a substring from may be of a character, numeric or date type, with a numeric or date expression being automatically converted to a character expression before taking the substring. The first position in the string is 1, and if length is set equal to 0 it means “until the end of the string”. The type returned is VARCHAR. When dragging a Substring operator into a variable, the following tree element is created.
Columns and/or other expressions can be moved into the (empty) branch of the tree. The starting position and length of the substring are specified in the Properties panel. Double-click on Substring, or highlight it and click Properties.