title: How to get the sum of employees in a salary grade
body: <p>So I have to show the number of employees in each salary grade. Employees and salgrade are their own tables. 
  ive tried:</p>
  
  <pre><code>select count(empno), grade
  from emp, salgrade
  group by grade
  order by grade;
  </code></pre>
  
  <p>but I get the sum of employees as the amount in the salary grade</p>
  
  <pre><code>COUNT(EMPNO)      GRADE
  ------------ ----------
        42          1
        42          2
        42          3
        42          4
        42          5
  </code></pre>
  
  <p>for some reason i cant get the query to list per grade salary. I tried different ways though i get random values like 0,9 etc</p>
  
  <pre><code>CREATE TABLE DEPT ( 
  DEPTNO NUMBER(2) NOT NULL, 
  DNAME CHAR(14), 
  LOC CHAR(13), 
  CONSTRAINT DEPT_PRIMARY_KEY PRIMARY KEY (DEPTNO)); 
  
  INSERT INTO DEPT VALUES (10,'ACCOUNTING','NEW YORK'); 
  INSERT INTO DEPT VALUES (20,'RESEARCH','DALLAS'); 
  INSERT INTO DEPT VALUES (30,'SALES','CHICAGO'); 
  INSERT INTO DEPT VALUES (40,'OPERATIONS','BOSTON'); 
  
  CREATE TABLE EMP ( 
  EMPNO NUMBER(4) NOT NULL, 
  ENAME CHAR(10), 
  JOB CHAR(9), 
  MGR NUMBER(4) CONSTRAINT EMP_SELF_KEY 
  REFERENCES EMP (EMPNO), 
  HIREDATE DATE, 
  SAL NUMBER(7,2), 
  COMM NUMBER(7,2), 
  DEPTNO NUMBER(2) NOT NULL, 
  CONSTRAINT EMP_FOREIGN_KEY FOREIGN KEY (DEPTNO) REFERENCES DEPT (DEPTNO), 
  CONSTRAINT EMP_PRIM_KEY PRIMARY KEY (EMPNO)); 
  
  INSERT INTO EMP VALUES (7839,'KING','PRESIDENT',NULL,'17-NOV-                    
  1981',5000,NULL,10); 
  INSERT INTO EMP VALUES (7698,'BLAKE','MANAGER',7839,'1-MAY-
  1981',2850,NULL,30); 
  INSERT INTO EMP VALUES (7782,'CLARK','MANAGER',7839,'9-JUN-
  1981',2450,NULL,10); 
  INSERT INTO EMP VALUES (7566,'JONES','MANAGER',7839,'2-APR-
  1981',2975,NULL,20); 
  INSERT INTO EMP VALUES (7654,'MARTIN','SALESMAN',7698,'28-SEP-
  1981',1250,1400,30); 
  INSERT INTO EMP VALUES (7499,'ALLEN','SALESMAN',7698,'20-FEB-
  1981',1600,300,30); 
  INSERT INTO EMP VALUES (7844,'TURNER','SALESMAN',7698,'8-SEP-
  1981',1500,0,30); 
  INSERT INTO EMP VALUES (7900,'JAMES','CLERK',7698,'3-DEC-1981',950,NULL,30); 
  INSERT INTO EMP VALUES (7521,'WARD','SALESMAN',7698,'22-FEB-
  1981',1250,500,30); 
  INSERT INTO EMP VALUES (7902,'FORD','ANALYST',7566,'3-DEC-
  1981',3000,NULL,20); 
  INSERT INTO EMP VALUES (7369,'SMITH','CLERK',7902,'17-DEC-
  1980',800,NULL,20); 
  INSERT INTO EMP VALUES (7788,'SCOTT','ANALYST',7566,'09-DEC-
  1982',3000,NULL,20); 
  INSERT INTO EMP VALUES (7876,'ADAMS','CLERK',7788,'12-JAN-
  1983',1100,NULL,20); 
  INSERT INTO EMP VALUES (7934,'MILLER','CLERK',7782,'23-JAN-
  1982',1300,NULL,10); 
  
  CREATE TABLE SALGRADE ( 
  GRADE NUMBER, 
  LOSAL NUMBER, 
  HISAL NUMBER); 
  
  INSERT INTO SALGRADE VALUES (1,700,1200); 
  INSERT INTO SALGRADE VALUES (2,1201,1400); 
  INSERT INTO SALGRADE VALUES (3,1401,2000); 
  INSERT INTO SALGRADE VALUES (4,2001,3000); 
  INSERT INTO SALGRADE VALUES (5,3001,9999); 
  </code></pre>