基本查询：
实例表
1 示例表 2 --部门表 3 4 create table dept( 5 6 deptno int primary key,--部门编号 7 8 dname nvarchar(30),--部门名 9 10 loc nvarchar(30)--地址 11 12 ); 13 14 15 16 --雇员表 17 18 create table emp( 19 20 empno int primary key,--雇员号 21 22 ename nvarchar(30),--员工姓名 23 24 job nvarchar(30),--雇员工作 25 26 mrg int,--雇员上级 27 28 hiredate datetime,--入职时间 29 30 sal numeric(10,2),--薪水 31 32 comm numeric(10,2),--奖金 33 34 deptno int foreign key references dept(deptno)--设置外键 35 36 ); 37 38 39 40 insert into dept values (10,'ACCOUNTING','NEW YORK'); 41 42 insert into dept values (20,'RESEARCH','DALLAS'); 43 44 insert into dept values (30 ,'SALES','CHICAGO'); 45 46 insert into dept values (40, 'OPERATIONS','BOSTON'); 47 48 49 50 insert into emp values (7369,'SMITH','CLERK',7902,'1980-12-17',800.00,null,20); 51 52 insert into emp values(7499,'ALLEN','SALESMAN',7698,'1981-2-20',1600.00,300.00,30); 53 54 insert into emp values(7521,'WARD','SALESMAN',7698,'1981-2-22',1250.00,500.00,30); 55 56 insert into emp values(7566,'JONES','MANAGER',7839,'1981-4-2',2975.00,null,20); 57 58 insert into emp values(7654,'MARTIN','SALESMAN',7698,'1981-9-28',1250.00,1400.00,30); 59 60 insert into emp values(7698,'BLAKE','MANAGER',7839,'1981-5-1',2850.00,null,30); 61 62 insert into emp values(7782,'CLARK','MANAGER',7839,'1981-6-9',2450.00,null,10); 63 64 insert into emp values(7788,'SCOTT','ANALYST',7566,'1987-4-19',3000.00,null,20); 65 66 insert into emp values(7839,'KING','PRESIDENT',null,'1981-11-17',5000.00,null,10); 67 68 insert into emp values(7844,'TURNER','SALESMAN',7698,'1981-9-8',1500.00,0.00,30); 69 70 insert into emp values(7876,'ADAMS','CLERK',7788,'1987-5-23',1100.00,null,20); 71 72 insert into emp values(7900,'JAMES','CLERK',7698,'1981-12-3',950.00,null,30); 73 74 insert into emp values(7902,'FORD','ANALYST',7566,'1981-12-3',3000.00,null,20); 75 76 insert into emp values(7934,'MILLER','CLERK',7782,'1982-1-23',1300.00,null,10);