MySQL表关联如何避免数据冲突

SELECT *
FROM table1
INNER JOIN table2 ON table1.id = table2.id;

-- LEFT JOIN
SELECT *
FROM table1
LEFT JOIN table2 ON table1.id = table2.id;

-- RIGHT JOIN
SELECT *
FROM table1
RIGHT JOIN table2 ON table1.id = table2.id;

SELECT DISTINCT table1.*, table2.*
FROM table1
INNER JOIN table2 ON table1.id = table2.id;

SELECT table1.*, table2.*
FROM table1
INNER JOIN table2 ON table1.id = table2.id
GROUP BY table1.id
HAVING COUNT(*) > 1;

SELECT *
FROM table1
WHERE NOT EXISTS (
    SELECT 1
    FROM table2
    WHERE table1.id = table2.id
);

-- INSERT IGNORE
INSERT IGNORE INTO table1 (column1, column2)
VALUES ('value1', 'value2');

-- REPLACE INTO
REPLACE INTO table1 (column1, column2)
VALUES ('value1', 'value2');