1. inner join 内連接配接查詢
SELECT a.*,b.* FROM table_a a INNER JOIN table_b b ON a.id=b.id；
2. left join 左關聯查詢
SELECT a.*,b.* FROM table_a a LEFT JOIN table_b b ON a.id=b.id；
3.right join 右關聯查詢
SELECT a.*,b.* FROM table_a a RIGHT JOIN table_b b ON a.id=b.id；
4.左連接配接-内連接配接
SELECT a.*,b.* FROM table_a a LEFT JOIN table_b b ON a.id=b.id WHERE b.id IS NULL；
5. 右連接配接-内連接配接
SELECT a.*,b.* FROM table_a a RIGHT JOIN table_b b ON a.id=b.id WHERE a.id IS NULL