MySQL ভিউ তৈরিতে লজিক্যাল অপারেটর (AND, OR, NOT) ব্যবহার

MySQL ভিউ তৈরি করার সময় লজিক্যাল অপারেটর AND, OR, NOT ব্যবহার করা যায়।

AND অপারেটরসহ ভিউ

AND দুটি এক্সপ্রেশন তুলনা করে, দুটোই সত্য হলে true রিটার্ন করে।

উদাহরণ

mysql> SELECT * FROM Student_info;
+------+---------+------------+------------+
| id   | Name    | Address    | Subject    |
+------+---------+------------+------------+
|  101 | YashPal | Amritsar   | History    |
|  105 | Gaurav  | Chandigarh | Literature |
|  125 | Raman   | Shimla     | Computers  |
|  130 | Ram     | Jhansi     | Computers  |
|  132 | Shyam   | Chandigarh | Economics  |
|  133 | Mohan   | Delhi      | Computers  |
+------+---------+------------+------------+

mysql> CREATE OR REPLACE VIEW Info AS
    -> SELECT ID, Name, Address, Subject
    -> FROM Student_info WHERE (Subject = 'Computers' AND ADDRESS = 'DELHI');
Query OK, 0 rows affected (0.13 sec)

mysql> SELECT * FROM Info;
+------+-------+---------+-----------+
| ID   | Name  | Address | Subject   |
+------+-------+---------+-----------+
|  133 | Mohan | Delhi   | Computers |
+------+-------+---------+-----------+

OR অপারেটরসহ ভিউ

OR দুটি এক্সপ্রেশন তুলনা করে, কমপক্ষে একটি সত্য হলে true রিটার্ন করে।

উদাহরণ

mysql> CREATE OR REPLACE VIEW Info AS
    -> SELECT ID, Name, Address, Subject
    -> FROM Student_info WHERE (Subject = 'Computers' OR ADDRESS = 'Amritsar');
Query OK, 0 rows affected (0.06 sec)

mysql> SELECT * FROM Info;
+------+---------+----------+-----------+
| ID   | Name    | Address  | Subject   |
+------+---------+----------+-----------+
|  101 | YashPal | Amritsar | History   |
|  125 | Raman   | Shimla   | Computers |
|  130 | Ram     | Jhansi   | Computers |
|  133 | Mohan   | Delhi    | Computers |
+------+---------+----------+-----------+

NOT অপারেটরসহ ভিউ

NOT একক অপারেন্ড নেয়। অপারেন্ড TRUE হলে 0, FALSE হলে 1 রিটার্ন করে।

উদাহরণ

mysql> CREATE OR REPLACE VIEW Info AS
    -> SELECT ID, Name, Address, Subject
    -> FROM Student_info WHERE Subject != 'Computers';
Query OK, 0 rows affected (0.06 sec)

mysql> SELECT * FROM Info;
+------+---------+------------+------------+
| ID   | Name    | Address    | Subject    |
+------+---------+------------+------------+
|  101 | YashPal | Amritsar   | History    |
|  105 | Gaurav  | Chandigarh | Literature |
|  132 | Shyam   | Chandigarh | Economics  |
+------+---------+------------+------------+