@NUMSTR
Use the @NUMSTR function to convert a string (character) column or value into a number. Use @NUMSTR to do either of the following:
                  
- 
                        Map a string (character) to a number. 
- 
                        Use a string column that contains only numbers in an arithmetic expression. 
Syntax
@NUMSTR (input)
               Example
PAGE_NUM = @NUMSTR (ALPHA_PAGE_NO)