Re: Finding largest key in Oracle using SQL commands?

Billy's answer is great for date or number keys, but if you are looking for the longest VARCHAR2 key then use
SELECT MAX(LENGTH(key_column_name) FROM table_name

Or, to find the distribution of key lengths, try this: SELECT LENGTH(key_column_name) keylength, COUNT(*) quantity FROM table_name
GROUP BY LENGTH(key_column_name)
ORDER BY keylength DESC

Martin Doherty

Billy Verreynne wrote:

>Keith Lee wrote:
>
>
>
>>Does anyone know how to find the largest key in an Oracle database using
>>SQL commands? I could open use a PL/SQL procedure to loop through the
>>table until I get to the largest key; but, I was wondering if there was
>>any SQL command to do this.
>>
>>
>
>You're looking for the MAX() function.
>
>Something like:
>SELECT MAX(age) FROM employees
>
>..which will give you the age of the oldest employee(s).
>
>I suggest that you spend some time with the Oracle SQL manual - SQL can do
>some pretty impressive stuff without needing to resort to PL/SQL or other
>languages.
>
>Remember that the secret of data processing in a database, is to let the
>database do all the work. SQL does exactly that. As soon as you use PL/SQL
>or any other language, _you_ do the processing with your code. Most of the
>time, this will be row-by-row processing. And several orders of magnitude
>slower than using SQL.
>
>So little grasshopper, the better you know SQL, the better your database
>kung fu. ;-)
>
>
>--
>Billy
>
Received on Wed Dec 04 2002 - 14:22:06 CST