1、內連接(交集部分)
SELECT <select_list>
FROM b
INNER JOIN b
ON a.key=b.key
2、
SELECT <select_list>
FROM b
LEFT JOIN b
ON a.key=b.key
3、
SELECT <select_list>
FROM b
RIGHT JOIN b
ON a.key=b.key
4、
SELECT <select_list>
FROM b
LEFT JOIN b
ON a.key=b.key
WHERE b.key is null;
5、
SELECT <select_list>
FROM b
RIGHT JOIN b
ON a.key=b.key
WHERE a.key is null;
6、
SELECT <select_list>
FROM a
FULL JOIN b
ON a.key=b.key
7、
SELECT <select_list>
FROM a
RIGHT JOIN b
ON a.key=b.key
WHERE a.key is null
OR b.key is null;