How to Simulate the MINUS Operation in MySQL?

MySQL Equivalent of MINUS Operation

MySQL does not natively support the MINUS operation, which is commonly used in Oracle databases. However, it provides an alternative approach to exclude records using the NOT IN condition.

Problem Statement

You have three tables:

• Service_Details: Stores service details
• Servicing_States: Lists states where services are offered
• Exception: Indicates areas where services are not offered

You want to combine the results of two SELECT queries to obtain a list of services that are offered in some states but not in others, effectively performing a MINUS operation.

Solution

To achieve this, you can use the following query:

SELECT Service_Code
FROM Service_Details
WHERE Service_Code IN (
  SELECT Service_Code
  FROM Servicing_States
  WHERE State NOT IN (
    SELECT State
    FROM Exception
    WHERE Zipcode = <ZIP CODE>
  )
);

Explanation

This query performs the following steps:

1. Selects the Service_Code from Service_Details.
2. Filters the results to include only Service_Code values that exist in the Servicing_States table.
3. Removes any Service_Code values that are present in the Exception table with the specified ZIP code.

The resulting list represents the services that are offered in some states but not in the specified ZIP code, effectively simulating the MINUS operation.

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