Using combined queries

Combined queries are a form of advanced querying technique that uses several queries for comparison in order to return a single dataset.

Using combined queries enables us to retrieve results from more than one query into a single table by comparing the rows of each query while a subquery compares a single object result.

Combined queries can use the following operators:

• Union: This will include the rows from both queries (this is also the default operator and is similar to the OR operator between query filters)

• Intersection: This includes the rows that are common to both queries (just like the AND operator between query filters)

• Minus: This includes the rows from the first query minus the rows from the second query

  

When building combined queries, the order, data type, and number of result objects has to be the same; however, there is no limitation to the number of query filters.

Getting ready

We are required to use the Island Resorts Marketing universe this time as our data...