Comparing Data With CHECKSUM

David Fowler shows how to use CHECKSUM and CHECKSUM_AGG to compare data:

There are times when we need to compare two tables and figure out if the data matches. I often see a number of ways of doing this suggested, most are quite slow and inefficient. I’d quite like to share a quick and slightly dirty way of doing this using the CHECKSUM and CHECKSUM_AGG functions.

Just a reminder that CHECKSUM() will generate a checksum for an entire row or selection of columns in the row.

Will generate a checksum for a dataset.

David then has a couple of examples showing these in action.

Related Posts

Pivoting Performance Counter Data

Dave Bland shows how you can build a dynamic pivot to see performance counter data over a stretch of time: The next step is to write the code to capture the counter values and insert the data it the temporary table created above.  Because we need to capture the values over a period of time, […]

Read More

Near-Zero Downtime Identity Column Changes

I’m getting close to the end of my series on near-zero downtime deployments. This latest post involves identity column changes: There are some tables where you create an identity value and expect to cycle through data. An example for this might be a queue table, where the data isn’t expected to live permanently but it […]

Read More


December 2018
« Nov Jan »