{"id":98914,"date":"2021-01-12T11:00:00","date_gmt":"2021-01-12T09:00:00","guid":{"rendered":"https:\/\/examples.javacodegeeks.com\/?p=98914"},"modified":"2021-02-19T15:42:42","modified_gmt":"2021-02-19T13:42:42","slug":"sql-intersect-example","status":"publish","type":"post","link":"https:\/\/examples.javacodegeeks.com\/sql-intersect-example\/","title":{"rendered":"SQL Intersect Example"},"content":{"rendered":"

1. Introduction<\/h2>\n

In this article, we will look at the Intersect operation. SQL Set Theory contains the Intersect. Most of the RDBMS like Oracle, SQL Server, and PostgreSQL support the Intersect operator. However, MySQL does not. In this article, we will understand what the Intersect operator is and how to emulate it in MySQL.<\/p>\n

2. What does Set Theory mean?<\/h2>\n

In SQL, an entity that can hold a collection of objects is called a \u201cset\u201d. Hence in SQL all \u201cRelations\u201d i.e. tables are sets. Set Theory is the set of operations in which objects from multiple sets merge to form a single result. In other words, the set operators combine multiple select queries to give a single result.<\/p>\n

The SQL Set operators are UNION, INTERSECT, and EXCEPT. Out of these operators, MySQL supports only UNION. It does not support the Intersect and Except keywords. However, MySQL emulates these operations using Joins and\/or subqueries.<\/p>\n

3. What is Intersect Operator?<\/h2>\n

The Intersect operator is the intersection of 2 or more datasets. In Relational Algebra, the intersection is shown with \ua4f5 symbol. The Venn diagram representation of the intersect operator is as follows<\/p>\n

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\"sql<\/a>
Intersect operator Venn Diagram<\/figcaption><\/figure>\n<\/div>\n

In SQL, the basic syntax of the Intersect operator is as follows:<\/p>\n

SELECT [column_names or *]\nFROM tables\n[WHERE conditions]\n\nINTERSECT\n\nSELECT [column_names or *]\nFROM tables\n[WHERE conditions];\n<\/pre>\n
As per MySQL Theory<\/p>\n
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The intersect, except and Minus statements are not elementary since they can be composed with other commands. Thus, they are not implemented.<\/p>\n
Unknown Source<\/cite><\/p><\/blockquote>\n
4. How to Emulate Intersect in MySQL<\/h2>\n
To get the effect of the Intersect operator, we can use the following methods in MySQL RDBMS.<\/p>\n