公式中没有错误，但是当我进入某些页面时，出现“字符串非数字”错误，并且我无法再预览报告

Question

I'm fairly new to programming and am currently teaching myself Crystal Reports...

I have a formula that has no errors in it but when I get to a certain page in the report, it gives me a message saying "This string is non-numeric".

Here is the formula, any help is very much appreciated!

select {@Upright/Grand}
case "Grand" : if tonumber({scsub.sub_desc}[1]) < 6 then 'Under 6' & chr(146)
else
if tonumber({scsub.sub_desc}[1]) = 6 then '6' & chr(146) & chr(150) & '7' & chr(146)
else
if tonumber({scsub.sub_desc}[1]) > 6 then '7' & chr(146) & chr(43) 
default : if tonumber({sccat.cat_desc} [1]) <= 42 then '44' & chr(34) & ' and Under' 
else
if tonumber({sccat.cat_desc} [1])  in 45 _to_ 48 then '45' & chr(34) & chr(150) & '48' & chr(34)
else
if tonumber({sccat.cat_desc} [1])  in 49 to 52 then '49' & chr(34) & chr(150) & '52' & chr(34)

Answer 1

You should start by adding a 'else' value in case all your 'if' cases are not verified. Then you should make sure that the {sccat.cat_desc} [1] returns only string values that can be converted to numbers: no nulls, no empty strings, no spaces, no characters, no nothing: just plain numbers.

Answer 2

Problem is with tonumber function where you are trying to convert a non numeric value into numeric... hence this error.

You have two options:

1. First test the field is numeric or not using IsNumeric and if the result is true then proceed with your calculation. Something like this

     if IsNumeric({scsub.sub_desc}[1]) then //your code 

2. Instead of converting the field to numeric value convert the comparision value to String that will be more usefult a less error prone. Somrthing like this.

     if {scsub.sub_desc}[1] < ToText(6) then 'Under 6' & chr(146)