Question

If I submit the following SQL statement to a database:

SELECT setting_value 
  FROM dba.system_settings 
 WHERE setting_name = 'RequestWebServiceURL' 
    OR setting_name = 'UNITS' 
    OR setting_name = 'FACTOR'

I get results in this order:

setting_value
---------------
www.requestURL 
1 
degrees

Even though I had specified “UNIT” before “FACTOR” in the SQL.

The table is, however, sorted by setting_name, which is why I got results in this order. May be a silly question but the order of the result based on the above query be preserved? Database in this case is Sybase.

Answer 1

The ANSI means would be to use a CASE expression in the ORDER BY clause:

  SELECT setting_value 
    FROM dba.system_settings 
   WHERE setting_name IN ('RequestWebServiceURL', 'UNITS', 'FACTOR')
ORDER BY CASE setting_name
           WHEN 'RequestWebServiceURL' THEN 1
           WHEN 'UNITS' THEN 2
           WHEN 'FACTOR' THEN 3
           ELSE 4
         END

An ORDER BY clause is the only means of guaranteeing result set order. Otherwise, you’re likely to see insertion order.