在SQL中，可以通过使用JOIN操作和WHERE子句来比较两张表的差异。以下是一种常见的方法：
SELECT table1.*
FROM table1
LEFT JOIN table2 ON table1.key = table2.key
WHERE table2.key IS NULL;
SELECT table2.*
FROM table1
RIGHT JOIN table2 ON table1.key = table2.key
WHERE table1.key IS NULL;
SELECT *
FROM table1
FULL JOIN table2 ON table1.key = table2.key
WHERE table1.key IS NULL OR table2.key IS NULL;
通过以上方法，可以找出两张表之间的差异并进行比较。
