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ORDER BY
Оператор ORDER BY используется для сортировки вывода по определенному полю, по возрастанию или убыванию. Для этого он добавляется к оператору SELECT.
Если выполнить простой запрос SELECT, вывод будет таким:
new_db.db> SELECT * from switch;
+----------------+----------+------------+-------------------+------------+-----------+
| mac | hostname | model | location | mngmt_ip | mngmt_vid |
+----------------+----------+------------+-------------------+------------+-----------+
| 0010.D1DD.E1EE | sw1 | Cisco 3850 | London, Green Str | 10.255.1.1 | 255 |
| 0020.A2AA.C2CC | sw2 | Cisco 3850 | London, Green Str | 10.255.1.2 | 255 |
| 0040.A4AA.C2CC | sw4 | Cisco 3850 | London, Green Str | 10.255.1.4 | 255 |
| 0050.A5AA.C3CC | sw5 | Cisco 3850 | London, Green Str | 10.255.1.5 | 255 |
| 0060.A6AA.C4CC | sw6 | C3750 | London, Green Str | 10.255.1.6 | 255 |
| 0070.A7AA.C5CC | sw7 | Cisco 3650 | London, Green Str | 10.255.1.7 | 255 |
| 0030.A3AA.C1CC | sw3 | Cisco 3850 | London, Green Str | 10.255.1.3 | 255 |
+----------------+----------+------------+-------------------+------------+-----------+
7 rows in set
Time: 0.039s
С помощью оператора ORDER BY можно вывести записи в таблице switch, отсортировав их по имени коммутаторов:
new_db.db> SELECT * from switch ORDER BY hostname ASC;
+----------------+----------+------------+-------------------+------------+-----------+
| mac | hostname | model | location | mngmt_ip | mngmt_vid |
+----------------+----------+------------+-------------------+------------+-----------+
| 0010.D1DD.E1EE | sw1 | Cisco 3850 | London, Green Str | 10.255.1.1 | 255 |
| 0020.A2AA.C2CC | sw2 | Cisco 3850 | London, Green Str | 10.255.1.2 | 255 |
| 0030.A3AA.C1CC | sw3 | Cisco 3850 | London, Green Str | 10.255.1.3 | 255 |
| 0040.A4AA.C2CC | sw4 | Cisco 3850 | London, Green Str | 10.255.1.4 | 255 |
| 0050.A5AA.C3CC | sw5 | Cisco 3850 | London, Green Str | 10.255.1.5 | 255 |
| 0060.A6AA.C4CC | sw6 | C3750 | London, Green Str | 10.255.1.6 | 255 |
| 0070.A7AA.C5CC | sw7 | Cisco 3650 | London, Green Str | 10.255.1.7 | 255 |
+----------------+----------+------------+-------------------+------------+-----------+
7 rows in set
Time: 0.034s
По умолчанию сортировка выполняется по возрастанию, поэтому в запросе можно было не указывать параметр ASC:
new_db.db> SELECT * from switch ORDER BY hostname;
+----------------+----------+------------+-------------------+------------+-----------+
| mac | hostname | model | location | mngmt_ip | mngmt_vid |
+----------------+----------+------------+-------------------+------------+-----------+
| 0010.D1DD.E1EE | sw1 | Cisco 3850 | London, Green Str | 10.255.1.1 | 255 |
| 0020.A2AA.C2CC | sw2 | Cisco 3850 | London, Green Str | 10.255.1.2 | 255 |
| 0030.A3AA.C1CC | sw3 | Cisco 3850 | London, Green Str | 10.255.1.3 | 255 |
| 0040.A4AA.C2CC | sw4 | Cisco 3850 | London, Green Str | 10.255.1.4 | 255 |
| 0050.A5AA.C3CC | sw5 | Cisco 3850 | London, Green Str | 10.255.1.5 | 255 |
| 0060.A6AA.C4CC | sw6 | C3750 | London, Green Str | 10.255.1.6 | 255 |
| 0070.A7AA.C5CC | sw7 | Cisco 3650 | London, Green Str | 10.255.1.7 | 255 |
+----------------+----------+------------+-------------------+------------+-----------+
7 rows in set
Time: 0.034s
Сортировка по IP-адресу по убыванию:
SELECT * from switch ORDER BY mngmt_ip DESC;
+----------------+----------+------------+-------------------+------------+-----------+
| mac | hostname | model | location | mngmt_ip | mngmt_vid |
+----------------+----------+------------+-------------------+------------+-----------+
| 0070.A7AA.C5CC | sw7 | Cisco 3650 | London, Green Str | 10.255.1.7 | 255 |
| 0060.A6AA.C4CC | sw6 | C3750 | London, Green Str | 10.255.1.6 | 255 |
| 0050.A5AA.C3CC | sw5 | Cisco 3850 | London, Green Str | 10.255.1.5 | 255 |
| 0040.A4AA.C2CC | sw4 | Cisco 3850 | London, Green Str | 10.255.1.4 | 255 |
| 0030.A3AA.C1CC | sw3 | Cisco 3850 | London, Green Str | 10.255.1.3 | 255 |
| 0020.A2AA.C2CC | sw2 | Cisco 3850 | London, Green Str | 10.255.1.2 | 255 |
| 0010.D1DD.E1EE | sw1 | Cisco 3850 | London, Green Str | 10.255.1.1 | 255 |
+----------------+----------+------------+-------------------+------------+-----------+
7 rows in set
Time: 0.034s