mysql full join

MySQL does not support FULL JOIN directly, but we can simulate it using UNION and LEFT/RIGHT JOINs.

For example, if we have two tables A and B, and we want to perform a FULL JOIN on them based on a common column "id", we can use the following query:

SELECT *
FROM A
LEFT JOIN B ON A.id = B.id
UNION
SELECT *
FROM A
RIGHT JOIN B ON A.id = B.id
WHERE A.id IS NULL;

The first part of the query performs a LEFT JOIN, which returns all rows from table A and matching rows from table B. The second part performs a RIGHT JOIN, which returns all rows from table B and matching rows from table A. The WHERE clause filters out the rows that were already returned by the LEFT JOIN.

The result of this query will contain all rows from both tables, with NULL values in the columns where there is no match.

Note that this approach can be slow for large tables, and it may be more efficient to use a different database system that supports FULL JOIN natively.