【正文】
是否報錯,為什么?SELECT ENAME,SAL FROM EMP WHERE SAL 39。 SELECT * FROM DEPT。 說明:IS NULL是判斷某個字段是否為空,為空并不等價于為空字符串或為數(shù)字0; 而 =NULL 是判斷某個值是否等于 NULL,NULL = NULL和NULL $amp。SALESMAN39。SALESMAN39。 和SALESMAN,年薪在15000 和20000 之間的員工的信息:名字、職位、年薪。 到1500 之間的員工信息:名字、工資,按工資從大到小排序。)。SALES39。 select ename,sal+m,m from emp where m in (select m from emp) order by sal+m desc,m desc SELECT ENAME,SAL + COMM AS WAGE,COMM FROM ORDER BY WAGE,COMM DESC。%A%39。 select ename from emp where ename like 39。 group by deptno。 select ,(select count(deptno) from emp b where = group by ) as deptcount from dept a 。 select (select from dept b where =) as deptname ,count(deptno) as deptcount,avg(sal) as deptavgsal from emp a group by deptno。 select , fro