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The INTERSECT command in SQL combines the results of two SQL statement and returns only data that are present in both SQL statements.
INTERSECT can be thought of as an AND operator (value is selected only if it appears in both statements), while UNION and UNION ALL can be thought of as an OR operator (value is selected if it appears in either the first or the second statement).
The syntax for INTERSECT is as follows:
[SQL Statement 1]
[SQL Statement 2];
The columns selected in [SQL Statement 1] and [SQL Statement 2] need to be of the same data type for INTERSECT to work.
We use the following tables for our example.
To find out all the dates where there are both store sales and internet sales, we use the following SQL statement:
SELECT Txn_Date FROM Store_Information
SELECT Txn_Date FROM Internet_Sales;
Please note that the INTERSECT command will only return distinct values.