Check out the solution in the video TSQL: Compare Tables. As you can see, we compare data in the two tables to identify where rows of data don't match (or don't exist). There are other techniques we can use to solve this.
Some examples we see in the video:
- Handling data that doesn't match
- Rows that may not exist
- What we don't look at
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When solving for this problem, we want to consider performance. Be careful about looking at more data than required - for instance, it's possible that we may only want to compare the identifiers in the tables. We may have the same identifiers, but other columns of data differ (very costly, but possible).
YouTube | Automating ETL | T-SQL In 2 Hours | Consumer Guide To Digital Security