Mysql, update multiple tables with one query

Update protocol: Best practices

Your relational integrity lifeline

Let's uphold the validity of data in our updates. A thorough JOIN condition establishes the right links between tables, mitigating the risk of inconsistent updates. Review your UPDATE target with a SELECT statement:

SELECT *
FROM table1
JOIN table2 ON table1.id = table2.ref_id
WHERE condition;


This dry run confirms the implications of your UPDATE action.

Database "gym" session: Reduce and optimize

In a single query, update multiple tables to enhance performance. A JOIN condition compresses SQL statements, reducing the room for error, ensuring consistency and optimizing table interplay.

Not all updates are created equal

An INNER JOIN targets the shared points between tables. Conversely, LEFT OUTER JOIN includes unmatched records.

UPDATE table1
LEFT JOIN table2 ON table1.id = table2.ref_id
SET table1.col = 'newVal1', table2.col = (CASE WHEN table2.col IS NULL THEN 'defaultVal' ELSE 'newVal2' END)
WHERE condition;


Tailor-made safety net: Stored procedures

For complex task management, stored procedures are your best friend. They pack sequential updates like a perfect lunchbox, providing rollback mechanisms to revert changes when needed. Your data consistency will thank you for it.

Critical scenarios: Got you covered

Placeholder records to the rescue

When dealing with placeholder records, keep your data integrity intact by setting default values when specific conditions play out. This ensures your table rows are healthy and valid regardless of data quirks.

Performance: The rubber meets the road

The power of your UPDATE-JOIN commands and their impact on your system's performance can't be underestimated, especially for large record volumes. Keep an eagle eye on the MySQL documentation for staying up-to-speed with optimization techniques.

Practical approach: Real-world implications

Beyond update: Select and insert made easy

Your task may require selection or insertion of data alongside updates. Face it like a Pro:

--We are logging here! Say hi to your auditor 
INSERT INTO log_table (description)
SELECT 'Updating tables' FROM dual
WHERE EXISTS (
    SELECT *
    FROM table1
  -- You like long SQL queries and you cannot lie
    JOIN table2 ON table1.id = table2.ref_id
    WHERE condition
);

UPDATE table1
JOIN table2 ON table1.id = table2.ref_id
SET table1.col = 'newVal1', table2.col = 'newVal2'
WHERE condition;


Untapped power: RIGHT JOIN & FULL OUTER JOIN

RIGHT JOIN or FULL OUTER JOIN (a combo of LEFT and RIGHT JOINS in MySQL) could be game changers, especially for diverse update needs spanning related tables.

Know your limits

Sorry to burst your bubble but MySQL doesn't support updating multiple tables with a FROM clause or MULTIPLE JOINS in the same way as SQL Server. Recognize this limitation and flex your adaptability muscle with multiple queries nested within a transaction.