how to know how many rows will be affected before running a query in microsoft sql server 2008

Question

i've read a bit about ROWCOUNT but its not exactly what im looking for. from my understanding rowcount states the number of rows affected AFTER you run the query. what im looking for is knowing BEFORE you run the query. is this possible?

Answer 1

You can also use BEGIN TRANSACTION before the operation is executed. You can see the number of rows affected. From there, either COMMIT the results or use ROLLBACK to put the data back in the original state.

BEGIN TRANSACTION;

UPDATE table
SET col = 'something'
WHERE col2 = 'something else';

Review changed data and then:

COMMIT;

or

ROLLBACK;