INTERSECT & EXCEPT

Syntax:

SELECT <SELECTION_FIELDS>
FROM <TABLES>
<OPTIONAL_ADDITIONAL_QUERY CRITERIA>
<INTERSECT OR EXCEPT>
SELECT <SELECTION_FIELDS>
FROM <TABLES>
<OPTIONAL_ADDITIONAL_QUERY CRITERIA>

Notes:
The number of fields in the <SELECTION_FIELDS> must be the same. The datatypes of the fields in the <SELECTION_FIELDS> need to be compatible.

Examples:

--Intersect
SELECT DISTINCT(CustomerID)
FROM SALES.CustomerTransactions ct
WHERE ct.TransactionDate BETWEEN '2016-01-01' AND '2016-12-31'
--263 records returned by this query
INTERSECT
SELECT DISTINCT(CustomerID)
FROM SALES.CustomerTransactions ct
WHERE ct.TransactionDate BETWEEN '2013-01-01' AND '2013-12-31'
--225 records returned by this query
--result is 225 records

--Except
SELECT DISTINCT(CustomerID)
FROM SALES.CustomerTransactions ct
WHERE ct.TransactionDate BETWEEN '2016-01-01' AND '2016-12-31'
--263 records returned by this query
EXCEPT
SELECT DISTINCT(CustomerID)
FROM SALES.CustomerTransactions ct
WHERE ct.TransactionDate BETWEEN '2013-01-01' AND '2013-12-31'
--225 returned by this query Records
--result is 38 records