MySQL এ শূন্য কোথায় নির্বাচন করুন?

নিম্নলিখিত সিনট্যাক্স −

select
yourColumnName1,
yourColumnName2,
yourColumnName3,
.
.
.
N
from yourTableName
where yourValue in(yourColumnName1,yourColumnName2) or yourColumnName1 is NULL;

আসুন একটি টেবিল তৈরি করি -

mysql> create table demo60
−> (
−> id int not null auto_increment primary key,
−> first_name varchar(20),
−> last_name varchar(20)
−> )
−> ;
Query OK, 0 rows affected (2.11 sec)

সন্নিবেশ কমান্ডের সাহায্যে টেবিলে কিছু রেকর্ড সন্নিবেশ করুন -

mysql> insert into demo60(first_name,last_name) values('John','Smith');
Query OK, 1 row affected (0.09 sec)

mysql> insert into demo60(first_name,last_name) values('John','Doe');
Query OK, 1 row affected (0.51 sec)

mysql> insert into demo60(first_name,last_name) values(null,'Brown');
Query OK, 1 row affected (0.09 sec)

mysql> insert into demo60(first_name,last_name) values('David','Miller');
Query OK, 1 row affected (0.16 sec)

mysql> insert into demo60(first_name,last_name) values('David','Smith');
Query OK, 1 row affected (0.11 sec)

mysql> insert into demo60(first_name,last_name) values('Chris','Brown');
Query OK, 1 row affected (0.12 sec)

সিলেক্ট স্টেটমেন্ট -

mysql> select *from demo60;

এটি নিম্নলিখিত আউটপুট −

+----+------------+-----------+
| id | first_name | last_name |
+----+------------+-----------+
|  1 | John       | Smith     |
|  2 | John       | Doe       |
|  3 | NULL       | Brown     |
|  4 | David      | Miller    |
|  5 | David      | Smith     |
|  6 | Chris      | Brown     |
+----+------------+-----------+
6 rows in set (0.00 sec)

NULL −

Mysql> select
−> id,
−> first_name,
−> last_name
−> from demo60
−> where 'John' in(first_name,last_name) or first_name is NULL;

এটি নিম্নলিখিত আউটপুট −

+----+------------+-----------+
| id | first_name | last_name |
+----+------------+-----------+
| 1  | John       | Smith     |
| 2  | John       | Doe       |
| 3  | NULL       | Brown     |
+----+------------+-----------+
3 rows in set (0.00 sec)