84669 person learning
152542 person learning
20005 person learning
5487 person learning
7821 person learning
359900 person learning
3350 person learning
180660 person learning
48569 person learning
18603 person learning
40936 person learning
1549 person learning
1183 person learning
32909 person learning
例如 A LEFT JOIN B 中A是主标还是字表
A是左表,B相当于子表,查询时A表全部内容都显示,B表中只会显示和A表中有交集的部分,B表不一定会全部显示
A是左表,B相当于子表,查询时A表全部内容都显示,B表中只会显示和A表中有交集的部分,B表不一定会全部显示