count null : COUNT « Aggregate Functions « Oracle PL / SQL






count null

   
SQL>
SQL>
SQL> CREATE TABLE EMP
  2  (EMPNO NUMBER(4) NOT NULL,
  3   ENAME VARCHAR2(10),
  4   JOB VARCHAR2(9),
  5   MGR NUMBER(4),
  6   HIREDATE DATE,
  7   SAL NUMBER(7, 2),
  8   COMM NUMBER(7, 2),
  9   DEPTNO NUMBER(2)
 10  );

Table created.

SQL>
SQL> INSERT INTO EMP VALUES (7369, 'SMITH',  'CLERK',     7902,TO_DATE('17-DEC-1980', 'DD-MON-YYYY'),  800, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7499, 'ALLEN',  'SALESMAN',  7698,TO_DATE('20-FEB-1981', 'DD-MON-YYYY'), 1600,  300, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7521, 'WARD',   'SALESMAN',  7698,TO_DATE('22-FEB-1981', 'DD-MON-YYYY'), 1250,  500, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7566, 'JONES',  'MANAGER',   7839,TO_DATE('2-APR-1981', 'DD-MON-YYYY'),  2975, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7654, 'MARTIN', 'SALESMAN',  7698,TO_DATE('28-SEP-1981', 'DD-MON-YYYY'), 1250, 1400, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7698, 'BLAKE',  'MANAGER',   7839,TO_DATE('1-MAY-1981', 'DD-MON-YYYY'),  2850, NULL, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7782, 'CLARK',  'MANAGER',   7839,TO_DATE('9-JUN-1981', 'DD-MON-YYYY'),  2450, NULL, 10);

1 row created.

SQL> INSERT INTO EMP VALUES (7788, 'SCOTT',  'ANALYST',   7566,TO_DATE('09-DEC-1982', 'DD-MON-YYYY'), 3000, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7839, 'KING',   'PRESIDENT', NULL,TO_DATE('17-NOV-1981', 'DD-MON-YYYY'), 5000, NULL, 10);

1 row created.

SQL> INSERT INTO EMP VALUES (7844, 'TURNER', 'SALESMAN',  7698,TO_DATE('8-SEP-1981', 'DD-MON-YYYY'),  1500,    0, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7876, 'ADAMS',  'CLERK',     7788,TO_DATE('12-JAN-1983', 'DD-MON-YYYY'), 1100, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7900, 'JAMES',  'CLERK',     7698,TO_DATE('3-DEC-1981', 'DD-MON-YYYY'),   950, NULL, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7902, 'FORD',   'ANALYST',   7566,TO_DATE('3-DEC-1981', 'DD-MON-YYYY'),  3000, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7934, null, 'CLERK',     7782,TO_DATE('23-JAN-1982', 'DD-MON-YYYY'), 1300, NULL, 10);

1 row created.

SQL>
SQL> select ename from emp;
ENAME
----------
SMITH
ALLEN
WARD
JONES
MARTIN
BLAKE
CLARK
SCOTT
KING
TURNER
ADAMS
JAMES
FORD


14 rows selected.

SQL>
SQL>
SQL> select count( ename ) from emp;
COUNT(ENAME)
------------
          13

1 row selected.

SQL>
SQL> drop table emp;

Table dropped.

SQL> --

   
    
  








Related examples in the same category

1.COUNT(column) and COUNT(*): count the number of rows passed into the function.
2.Syntax: COUNT([DISTINCT]|[ALL] )
3.Using GROUP BY would tell us how many cars from each vendor we have on the lot:
4.Find out which maker has a null value car with count()
5.-Using the COUNT function in Having clause
6.Example using the COUNT function with group by clause
7.Count with group by: count for a group value
8.Get the number of rows in each city group using the COUNT() function
9.Column alias name for count function
10.Count(*) - count(column_Name)
11.count distinct column value
12.count(1)
13.count(distinct state)
14.Count(*) and column renaming
15.Count() with where clause
16.Count date field value, and calculation
17.Count department and calculate average salary
18.Count employee in a department after grouping by department id
19.Count employee, group by department id and job title
20.count(*) - count(onhand)
21.count(*) vs count(column name)