MySQL में NULL मानों के अनुसार ऑर्डर करने की क्वेरी

उदाहरण

टेबल बनाएं:

mysql> create table DemoTable707 (
    -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
    -> StudentFirstName varchar(100),
    -> StudentMarks int
    -> );
Query OK, 0 rows affected (0.59 sec)

रिकॉर्ड डालें (कुछ NULL नाम के साथ):

mysql> insert into DemoTable707(StudentFirstName, StudentMarks) values('John', 45);
Query OK, 1 row affected (0.16 sec)
mysql> insert into DemoTable707(StudentFirstName, StudentMarks) values(NULL, 65);
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable707(StudentFirstName, StudentMarks) values('Chris', 78);
Query OK, 1 row affected (0.19 sec)
mysql> insert into DemoTable707(StudentFirstName, StudentMarks) values(NULL, 89);
Query OK, 1 row affected (0.19 sec)
mysql> insert into DemoTable707(StudentFirstName, StudentMarks) values('Robert', 99);
Query OK, 1 row affected (0.18 sec)
mysql> insert into DemoTable707(StudentFirstName, StudentMarks) values(NULL, 34);
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable707(StudentFirstName, StudentMarks) values('Mike', 43);
Query OK, 1 row affected (0.20 sec)

सभी रिकॉर्ड देखें:

mysql> select * from DemoTable707;

आउटपुट

+-----------+------------------+--------------+
| StudentId | StudentFirstName | StudentMarks |
+-----------+------------------+--------------+
| 1         | John             | 45           |
| 2         | NULL             | 65           |
| 3         | Chris            | 78           |
| 4         | NULL             | 89           |
| 5         | Robert           | 99           |
| 6         | NULL             | 34           |
| 7         | Mike             | 43           |
+-----------+------------------+--------------+
7 rows in set (0.00 sec)

NULL मानों के अनुसार ऑर्डर करने की क्वेरी:

mysql> select * from DemoTable707 order by StudentFirstName IS NULL, StudentFirstName DESC;

आउटपुट

+-----------+------------------+--------------+
| StudentId | StudentFirstName | StudentMarks |
+-----------+------------------+--------------+
| 5         | Robert           | 99           |
| 7         | Mike             | 43           |
| 1         | John             | 45           |
| 3         | Chris            | 78           |
| 2         | NULL             | 65           |
| 4         | NULL             | 34           |
| 6         | NULL             | 34           |
+-----------+------------------+--------------+
7 rows in set (0.00 sec)

व्याख्या: IS NULL TRUE (1) लौटाता है NULL के लिए, FALSE (0) नॉन-NULL के लिए। डिफॉल्ट ASC के साथ NULL अंत में आते हैं। DESC के साथ नॉन-NULL पहले, फिर नाम अवरोही क्रम में।