How do I sort a VARCHAR column in SQL server that contains numbers?

Question

I have a VARCHAR column in a SQL Server 2000 database that can contain either letters or numbers. It depends on how the application is configured o

Answer 1

you can always convert your varchar-column to bigint as integer might be too short...

select cast([yourvarchar] as BIGINT)

but you should always care for alpha characters

where ISNUMERIC([yourvarchar] +'e0') = 1

the +'e0' comes from http://blogs.lessthandot.com/index.php/DataMgmt/DataDesign/isnumeric-isint-isnumber

this would lead to your statement

SELECT
  *
FROM
  Table
ORDER BY
   ISNUMERIC([yourvarchar] +'e0') DESC
 , LEN([yourvarchar]) ASC

the first sorting column will put numeric on top. the second sorts by length, so 10 will preceed 0001 (which is stupid?!)

this leads to the second version:

SELECT
      *
    FROM
      Table
    ORDER BY
       ISNUMERIC([yourvarchar] +'e0') DESC
     , RIGHT('00000000000000000000'+[yourvarchar], 20) ASC

the second column now gets right padded with '0', so natural sorting puts integers with leading zeros (0,01,10,0100...) in correct order (correct!) - but all alphas would be enhanced with '0'-chars (performance)

so third version:

 SELECT
          *
        FROM
          Table
        ORDER BY
           ISNUMERIC([yourvarchar] +'e0') DESC
         , CASE WHEN ISNUMERIC([yourvarchar] +'e0') = 1
                THEN RIGHT('00000000000000000000' + [yourvarchar], 20) ASC
                ELSE LTRIM(RTRIM([yourvarchar]))
           END ASC

now numbers first get padded with '0'-chars (of course, the length 20 could be enhanced) - which sorts numbers right - and alphas only get trimmed