首先构建场景 相应表中数据如下: SELECT * FROM EMPLOYEE: SELECT * FROM DEPTINFO; 连接方式: 1. , SELECT E.EMPNAME, D.DEPNAME FROM EMPLOYEE E, DEPTINFO D WHERE E.DEPTID = D.DEPID ORDER BY DEPNAME; 由此可见“,”连接是将两张表进行等值连接 2.join SELECT E.EMPNAME, D.DEPNAME FROM EMPLOYEE E JOI