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The MINUS command operates on two SQL statements. It takes all the results from the first SQL statement, and then subtract out the ones that are present in the second SQL statement to get the final answer. If the second SQL statement includes results not present in the first SQL statement, such results are ignored.
The syntax is as follows:
[SQL Statement 1]
[SQL Statement 2];
Let's continue with the same example:
and we want to find out all the dates where there are store sales, but no internet sales. To do so, we use the following SQL statement:
SELECT Txn_Date FROM Store_Information
SELECT Txn_Date FROM Internet_Sales;
'Jan-05-1999', 'Jan-07-1999';, and 'Jan-08-1999' are the distinct values returned from SELECT Txn_Date FROM Store_Information. 'Jan-07-1999' is also returned from the second SQL statement, SELECT Txn_Date FROM Internet_Sales, so it is excluded from the final result set.
Please note that the MINUS command will only return distinct values.
Some databases may use EXCEPT instead of MINUS. Please check the documentation for your specific database for the correct usage.