How Can I Achieve the Functionality of SQL Server's INTERSECT Operator in MySQL?

Finding an Alternative to Intersect in MySQL

Microsoft SQL Server's INTERSECT operator allows one to retrieve distinct values that exist in common between two datasets. Unfortunately, MySQL does not provide a direct equivalent.

SQL Server Syntax:

INTERSECT
SELECT value FROM dataset1
SELECT value FROM dataset2

MySQL Alternatives:

Instead, MySQL offers alternative methods to achieve similar results:

Method 1: INNER JOIN with Distinct

This approach uses an INNER JOIN between the two datasets and applies the DISTINCT keyword to avoid duplicates:

SELECT DISTINCT value
FROM dataset1
INNER JOIN dataset2
USING (value);

Method 2: Subquery with IN

Another option is to use a subquery with IN to check for matching values:

SELECT value
FROM dataset1
WHERE value IN
(SELECT value FROM dataset2);

Example:

Consider the following MySQL tables:

CREATE TABLE table1 (id INT, value VARCHAR(255));
CREATE TABLE table2 (id INT, value VARCHAR(255));

INSERT INTO table1 VALUES (1, 'A'), (2, 'B'), (3, 'B');
INSERT INTO table2 VALUES (1, 'B');

-- Method 1
SELECT DISTINCT value
FROM table1
INNER JOIN table2
USING (value);

-- Method 2
SELECT value
FROM table1
WHERE value IN
(SELECT value FROM table2);

Both methods will return the following result:

+-------+
| value |
+-------+
| B     |
+-------+

When working with non-unique data, the DISTINCT keyword in Method 1 or the use of DISTINCT in the subquery in Method 2 ensures that only unique values are returned.

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