mysql数据表格操作实例

1、准备工作：create database java1707；创建数据库，并命名；创建表格emp：CREATE TABLE emp(字段，字段类型 empno INT, ename VARCHAR(50), job VARCHAR(50), mgr INT, hiredate DATE, sal DECIMAL(7,2), comm decimal(7,2), deptno INT) ;

3、INSERT INTO emp values(7654,'MARTIN','SAL呶蓟鹭毵ESMAN',7698,'1981-09-28',1250,1400,30);INSERT INTO emp values(7698,'BLAKE','MANAGER',7839,'1981-05-01',2850,NULL,30);INSERT INTO emp values(7782,'CLARK','MANAGER',7839,'1981-06-09',2450,NULL,10);INSERT INTO emp values(7788,'SCOTT','ANALYST',7566,'1987-04-19',3000,NULL,20);INSERT INTO emp values(7839,'KING','PRESIDENT',NULL,'1981-11-17',5000,NULL,10);

5、----查看表格SELECT * FROM emp;----将表格分组SELECT* FROM emp GROUP BY deptno;----查看表格中deptno=10 的所有数据SELECT *FROM emp WHERE deptno=10;----查询每个部门的部门编号和每个部门的工资和：SELECT deptno,SUM(sal) FROM emp GROUP BY deptno;SELECT deptno,SUM(sal) AS a FROM emp GROUP BY deptno;

6、----查询每个部门的部门编号以及每个部门的人数：SELECT deptno,COUNT(*) FROM emp GROUP BY deptno;