以前学习SQLite用过的,希望对你有帮助!!!
//主表
CREATE TABLE Teacher
(
id integer PRIMARY KEY autoincrement,
name TEXT not null
);
//从表
CREATE TABLE Student3
(
id integer PRIMARY KEY autoincrement,
laoshi INTEGER,
Foreign KEY(laoshi) REFERENCES Teacher(id)
);
//多表查询之全连接(full join),内连接基础上,把右边没有与左边任何项对应的左项设为null,把左边没有与右边任何项对应的右项设为null
具体要求规范:
1、两个表列数相同,列对应类型相同,并确保有相同顺序
自动实现:select * from Teacher full join Student3 on Teacher.id=Student3.laoshi;
2、两个表列数不一致
手动实现:select Teacher.*,Student3.* from Teacher left join Student3 on Teacher.id=Student3.laoshi
UNION
select Teacher.*,Student3.* from Student3 left join Teacher on Teacher.id=Student3.laoshi;