Set Operators
Set Operators
Learning Outcomes
- Learn how to perform a
INTERSECTof two queries. - Learn how to perform a
MINUSof two queries. - Learn how to perform a
UNIONof two queries. - Learn how to perform a
UNION ALLof two queries.
Lesson Materials
You can joins rows between two queries by several techniques. They all work by comparing all the columns returned by the top query with all the columns returned by the bottom query.
Unlike joins where you get to specify the columns that the join uses to match values, set operators match the SELECT-list of the two queries. The two queries must have the same SELECT-list columns, which is defined by position, column name, and data type. That means your choice of the SELECT-list columns determines the join conditions between the queries.
INTERSECT- The
INTERSECToperator returns the rows found in both queries. UNION- The
UNIONoperator returns the unique set of rows found in both queries. UNION ALL- The
UNION ALLoperator returns the unique set of rows found in one query but not the other and two copies of the rows found in both queries. MINUS- The
MINUSoperator returns the rows from the top query not found in the bottom query.
