Use the Substring expression type to extract and return characters from a string based on a character position (starting position) and substring length (number of characters to extract).

Use parameters that follow this form: substr(Dimension, position, length). For example, if the source Entity number is "031010," to return the substring starting from the second character position with a substring length of 5, specify: substr(Entity, 2, 5) as the expression. In this example, the expression returns: 31010.