Compare NULL with <=> operator : Operator « Select Clause « SQL / MySQL

1. SQL / MySQL
2. Select Clause
3. Operator

Compare NULL with <=> operator

      
mysql>
mysql> CREATE TABLE EmployeeS(
    ->          EmployeeNO       INTEGER      NOT NULL,
    ->          NAME           CHAR(15)     NOT NULL,
    ->          INITIALS       CHAR(3)      NOT NULL,
    ->          BIRTH_DATE     DATE                 ,
    ->          SEX            CHAR(1)      NOT NULL,
    ->          JOINED         SMALLINT     NOT NULL,
    ->          STREET         VARCHAR(30)  NOT NULL,
    ->          HOUSENO        CHAR(4)              ,
    ->          POSTCODE       CHAR(6)              ,
    ->          TOWN           VARCHAR(30)  NOT NULL,
    ->          PHONENO        CHAR(13)             ,
    ->          LEAGUENO       CHAR(4)              ,
    ->          PRIMARY KEY    (EmployeeNO)           );
Query OK, 0 rows affected (0.00 sec)

mysql> INSERT INTO EmployeeS VALUES (2, 'Jack', 'R', '1948-09-01', 'M', 1975, 'Stoney Road','43', '3575NH', 'Stratford', '070-237893', '2411');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO EmployeeS VALUES (6, 'Link', 'R', '1964-06-25', 'M', 1977, 'Haseltine Lane','80', '1234KK', 'Stratford', '070-476537', '8467');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO EmployeeS VALUES (7, 'Wise', 'GWS', '1963-05-11', 'M', 1981, 'First Way','39', '9758VB', 'Stratford', '070-347689', NULL);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO EmployeeS VALUES (8, 'Mary', 'B', '1962-07-08', 'F', 1980, 'Station Road','4', '6584WO', 'Inglewood', '070-458458', '2983');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO EmployeeS VALUES (27, 'Collins', 'DD', '1964-12-28', 'F', 1983, 'Long DRay','804', '8457DK', 'Eltham', '079-234857', '2513');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO EmployeeS VALUES (28, 'Collins', 'C', '1963-06-22', 'F', 1983, 'Old Main Road','10', '1294QK', 'Midhurst', '010-659599', NULL);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO EmployeeS VALUES (39, 'Bishop', 'D', '1956-10-29', 'M', 1980, 'Eaton Square','78', '9629CD', 'Stratford', '070-393435', NULL);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO EmployeeS VALUES (44, 'Baker', 'E', '1963-01-09', 'M', 1980, 'Lewis Street','23', '4444LJ', 'Inglewood', '070-368753', '1124');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO EmployeeS VALUES (57, 'Brown', 'M', '1971-08-17', 'M', 1985, 'First Way','16', '4377CB', 'Stratford', '070-473458', '6409');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO EmployeeS VALUES (83, 'Hope', 'PK', '1956-11-11', 'M', 1982, 'Main Road','16A', '1812UP', 'Stratford', '070-353548', '1608');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO EmployeeS VALUES (95, 'Miller', 'P', '1963-05-14', 'M', 1972, 'High Street','33A', '5746OP', 'Douglas', '070-867564', NULL);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO EmployeeS VALUES (100, 'Link', 'P', '1963-02-28', 'M', 1979, 'Haseltine Lane','80', '6494SG', 'Stratford', '070-494593', '6524');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO EmployeeS VALUES (104, 'Jane', 'D', '1970-05-10', 'F', 1984, 'Stout Street','65', '9437AO', 'Eltham', '079-987571', '7060');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO EmployeeS VALUES (112, 'Bailey', 'IP', '1963-10-01', 'F', 1984, 'Vixen Road','8', '6392LK', 'Plymouth', '010-548745', '1319');
Query OK, 1 row affected (0.00 sec)

mysql>
mysql>
mysql>
mysql> SELECT   EmployeeNO, LEAGUENO
    -> FROM     EmployeeS
    -> WHERE    LEAGUENO <=> NULL;
+------------+----------+
| EmployeeNO | LEAGUENO |
+------------+----------+
|          7 | NULL     |
|         28 | NULL     |
|         39 | NULL     |
|         95 | NULL     |
+------------+----------+
4 rows in set (0.00 sec)

mysql>
mysql> drop table Employees;
Query OK, 0 rows affected (0.00 sec)

mysql>

   
    
    
    
    
    
  

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