Question

I have 3 columns of data in SQL Server 2005 :

LASTNAME
FIRSTNAME
CITY

I want to randomly re-order these 3 columns (and munge the data) so that the data is no longer meaningful. Is there an easy way to do this? I don’t want to change any data, I just want to re-order the index randomly.

Answer 1

When you say “re-order” these columns, do you mean that you want some of the last names to end up in the first name column? Or do you mean that you want some of the last names to get associated with a different first name and city?

I suspect you mean the latter, in which case you might find a programmatic solution easier (as opposed to a straight SQL solution). Sticking with SQL, you can do something like:

UPDATE the_table
SET lastname = (SELECT lastname FROM the_table ORDER BY RAND())

Depending on what DBMS you’re using, this may work for only one line, may make all the last names the same, or may require some variation of syntax to work at all, but the basic approach is about right. Certainly some trials on a copy of the table are warranted before trying it on the real thing.

Of course, to get the first names and cities to also be randomly reordered, you could apply a similar query to either of those columns. (Applying it to all three doesn’t make much sense, but wouldn’t hurt either.)

Since you don’t want to change your original data, you could do this in a temporary table populated with all rows.

Finally, if you just need a single random value from each column, you could do it in place without making a copy of the data, with three separate queries: one to pick a random first name, one a random last name, and the last a random phone number.