As you can see the planning_committeetable is a subset of employees, meaning all of its data is also contained in employees.Įmployees- All of the employees employed at our company. More SQL INTERSECT and MINUS Examples One Table is a Subset of the Other Table’s Dataįor this scenario, imagine we have two tables called employeesand planning_committee. One table in your query contains no data.One table is the subset of the other table's data.Let us look at some more examples that show you how these operators will act in three different scenarios: This was a simple example showing you how the INTERSECT and MINUS operators can be used to quickly retrieve distinct datasets. You’ll also learn how to JOIN tables and add, modify, or remove data from a database. It will teach you basic SQL statements like WHERE, GROUP BY, ORDER BY, and HAVING. If you feel overwhelmed, consider trying the SQL Fundamentals track from, which will provide you with a solid SQL foundation. SQL starts with our suppliers table and then removes any countries that exist in the customers table. Let’s reverse the order of our SELECT clauses and see what happens.Įxecuting this query returns the following data: countryĪs you can see, our result set was wildly different. The order of your SELECT clauses is very important here, and it is something you must be mindful of when using the MINUS operator. There we have it: the countries that are unique to our customers table. ![]() This will allow us to get the countries in our customers table that are not in our suppliers table:Įxecuting this query yields the result: country Now let’s apply the MINUS operator to the same tables. Only the countries of France and Ireland are shared between the tables. Looking back over the customers and suppliers tables, we can see this result is correct. Executing this query results in the following data set: country We specify the country column in each SELECT clause. We want to find the countries that our suppliers and customers have in common. Suppliers - Contains details about our suppliers. Imagine we have the following tables.Ĭustomers- Contains details about our customers id Let’s apply the INTERSECT and MINUS clauses to a practical example. These are the records that exist in the first dataset and not the second. The MINUS query will return the records in the red area. The concept of SQL MINUS is further explained by this diagram: The SQL code shown in the square brackets is entirely optional. For databases like SQL Server, PostgreSQL, and SQLite, use the EXCEPT operator to perform this type of query. It can be used in databases like MySQL and Oracle. The MINUS operator is not supported in all SQL databases. SQL MINUS only returns rows that are not available in the second SELECT statement.Įach SELECT statement within a MINUS query must contain the same number of fields in the result sets along with similar data types. The SQL MINUS clause is used to combine two SELECT statements, but it returns rows from the first SELECT statement that are not returned by the second SELECT statement. If you’re interested in learning more, this article covers the different methods for combining the results of SQL queries. INTERSECT is just one way of merging the results of different SQL queries. These are the records that exist in both data sets The INTERSECT query will return the records in the shaded area. The concept of an INTERSECT is further explained by the following diagram: SELECT column_1 Īnything inside the square brackets is entirely optional. ![]() Here is the syntax for the INTERSECT operator: ![]() INTERSECT filters duplicates and returns only distinct rows that are common between all of the queries. The column data types must be the same, or at least compatible with one another. The number and order of the columns must be the same in all of the SELECT queries. If a record exists in one query and not in the other, it will be omitted from the INTERSECT results. However, it only returns the rows selected by all queries or data sets. The SQL INTERSECT operator is used to return the results of two or more SELECT statements.
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