In Oracle, how do I convert a number such as 1 to a string such as “1st”?

Question

I'd like to format a number as "1st", "2nd", "4th", "9th", etc. Is there an Oracle function that will do this for me?

Answer 1

Assuming the value supplied is numeric, rather than DATE, you can use TO_CHAR but you have to convert the numeric value to a string, then a DATE (Julian) before ultimately formatting it:

SELECT TO_CHAR(TO_DATE('1', 'dd'), 'ddth')
  FROM DUAL

Result:

01st

When testing, using 'd' for the format didn't return expected results because the value is interpreted as a Julian date. Either substring the output to remove the leading zero, or provide a full date string (doesn't matter to the TO_CHAR because it's only interested in the day of the month):

SELECT TO_CHAR(TO_DATE('1900-01-01', 'YYYY-MM-dd'), 'dth')
  FROM DUAL

Because calendar days end at 31, use the year value instead to handle numbers greater than 31:

SELECT TO_CHAR(TO_DATE('32-01-01', 'YYYY-MM-dd'), 'yyth')
  FROM DUAL

Result:

32nd

Answer 2

Maybe I'm oversimplifying, but it seems like the following should work just fine (for integers) and is a lot more readable than converting to a date and back:

select case 
       when initial_extent is null then null
       when substr(initial_extent,-2,1) = '1' 
            then initial_extent || 'th'
       else case substr(initial_extent,-1,1)
            when '1' then initial_extent || 'st'
            when '2' then initial_extent || 'nd'
            when '3' then initial_extent || 'rd'
            else initial_extent || 'th'
            end
       end as formatted_number
from user_tables

Answer 3

select  substr( to_char( to_date( abs( decode( mod( l_value, 10 ), 0, 4, mod( l_value , 10 )  ) ), 'YYYY' ), 'YTH' ), 2 ) as value
from    dual

Replace l_value with appropriate, hmmm, value. Should cover any numbers.