How Can I Efficiently INSERT INTO or UPDATE a Database Row Based on Two Conditions?

INSERT INTO or UPDATE with Two Conditions: An Efficient Solution

The task of inserting or updating rows in a database based on two conditions can be challenging, especially when seeking an efficient solution. This problem is particularly prevalent when dealing with tables where new rows are continually generated with duplicate names and dates.

The Solution: INSERT INTO ON DUPLICATE KEY UPDATE

The optimal solution for this problem is the INSERT INTO ON DUPLICATE KEY UPDATE statement. This statement allows for the insertion of a new row if it does not already exist, and updating an existing row if it does. To utilize this statement, the table must have a unique key (such as a composite key) to detect conflicts during the insert operation.

Example Usage

Consider a table with the following schema:

CREATE TABLE myThing (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name INT NOT NULL,
    values1 INT NOT NULL,
    values2 INT NOT NULL,
    dates DATE NOT NULL,
    UNIQUE KEY (name, dates) -- This unique key is crucial.
);

With this setup, the following statement will insert a new row if the name and date combination does not exist, or update the existing row if it does:

INSERT INTO myThing (name, values1, values2, dates)
VALUES (777, 1, 1, '2015-07-11')
ON DUPLICATE KEY UPDATE values2=values2+1;

Example Results

Executing the insert statement multiple times with the same name and date combination will update the values2 column, as seen below:

| id | name | values1 | values2 | dates      |
| --- | --- | --- | --- | --- |
| 1 | 777 | 1 | 4 | 2015-07-11 |

Conclusion

The INSERT INTO ON DUPLICATE KEY UPDATE statement provides a highly efficient solution for managing insertions and updates based on multiple conditions. By defining a unique key, this approach ensures that duplicate entries are handled appropriately, eliminating the need for complex stored procedures.

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