Question

I have two tables. Table 1 has about 80 rows and Table 2 has about 10 million.

I would like to update all the rows in Table 2 with a random row from Table 1. I don’t want the same row for all the rows. Is it possible to update Table 2 and have it randomly select a value for each row it is updating?

This is what I have tried, but it puts the same value in each row.

update member_info_test
set hostessid = (SELECT TOP 1 hostessId FROM hostess_test ORDER BY NEWID())

**Edited

Answer 1

Ok, I think that this is one of the weirdest query that I’ve wrote, and I think that this is gonna be terrible slow. But give it a shot:

UPDATE A
SET A.hostessid = B.hostessId
FROM member_info_test A
CROSS APPLY (SELECT TOP 1 hostessId
             FROM hostess_test 
             WHERE A.somecolumn = A.somecolumn
             ORDER BY NEWID()) B