MySql LEFT JOIN 问题
现在有两个表A_TBL B_TBL
A_TBL 数据如下:
id en
1 1
2 0
3 1
4 1
B_TBL 数据如下:
id aid en
11 1 1
12 2 1
13 3 0
14 3 1
15 4 1
16 2 1
17 5 1
(1)
SELECT * FROM A_TBL AS A
LEFT JOIN B_TBL AS B
ON B.aid = A.id
AND B.en = 1
WHERE A.en = 1
(2)
SELECT * FROM A_TBL AS A
LEFT JOIN B_TBL AS B
ON B.aid = A.id
AND B.en = 1
AND A.en = 1
请给我1,2两个查询结果. 并说出原因.
多谢.