SQL — Примеры операторов сравнения

Рассмотрим таблицу CUSTOMERS, имеющую следующие записи:

SQL> SELECT * FROM CUSTOMERS;

+----+----------+-----+-----------+----------+
| ID | NAME     | AGE | ADDRESS   | SALARY   |
+----+----------+-----+-----------+----------+
|  1 | Maxim    |  35 | Moscow    | 21000.00 |
|  2 | AndreyEx |  38 | Krasnodar | 55500.00 |
|  3 | Oleg     |  33 | Rostov    | 34000.00 |
|  4 | Masha    |  35 | Moscow    | 31500.00 |
|  5 | Ruslan   |  34 | Omsk      | 43000.00 |
|  6 | Dima     |  32 | SP        | 45000.00 |
|  7 | Roma     |  34 | SP        | 10000.00 |
+----+----------+-----+-----------+----------+
7 rows in set (0.00 sec)

Вот некоторые простые примеры, демонстрирующие использование операторов сравнения в SQL:

Пример 1

SQL> SELECT * FROM CUSTOMERS WHERE SALARY > 45000;

Вывод

+----+----------+-----+-----------+----------+
| ID | NAME     | AGE | ADDRESS   | SALARY   |
+----+----------+-----+-----------+----------+
|  2 | AndreyEx |  38 | Krasnodar | 55500.00 |
+----+----------+-----+-----------+----------+
1 rows in set (0.00 sec)

Пример 2

SQL>  SELECT * FROM CUSTOMERS WHERE SALARY = 55000;

Вывод

+----+----------+-----+-----------+----------+
| ID | NAME     | AGE | ADDRESS   | SALARY   |
+----+----------+-----+-----------+----------+
|  2 | AndreyEx |  38 | Krasnodar | 55500.00 |
+----+----------+-----+-----------+----------+
1 rows in set (0.00 sec)

Пример 3

SQL>  SELECT * FROM CUSTOMERS WHERE SALARY != 55000;

Вывод

+----+----------+-----+-----------+----------+
| ID | NAME     | AGE | ADDRESS   | SALARY   |
+----+----------+-----+-----------+----------+
|  1 | Maxim    |  35 | Moscow    | 21000.00 |
|  3 | Oleg     |  33 | Rostov    | 34000.00 |
|  4 | Masha    |  35 | Moscow    | 31500.00 |
|  5 | Ruslan   |  34 | Omsk      | 43000.00 |
|  6 | Dima     |  32 | SP        | 45000.00 |
|  7 | Roma     |  34 | SP        | 10000.00 |
+----+----------+-----+-----------+----------+
6 rows in set (0.00 sec)

Пример 4

SQL> SELECT * FROM CUSTOMERS WHERE SALARY <> 55000;

Вывод

+----+----------+-----+-----------+----------+
| ID | NAME     | AGE | ADDRESS   | SALARY   |
+----+----------+-----+-----------+----------+
|  1 | Maxim    |  35 | Moscow    | 21000.00 |
|  3 | Oleg     |  33 | Rostov    | 34000.00 |
|  4 | Masha    |  35 | Moscow    | 31500.00 |
|  5 | Ruslan   |  34 | Omsk      | 43000.00 |
|  6 | Dima     |  32 | SP        | 45000.00 |
|  7 | Roma     |  34 | SP        | 10000.00 |
+----+----------+-----+-----------+----------+
6 rows in set (0.00 sec)

Пример 5

SQL> SELECT * FROM CUSTOMERS WHERE SALARY >= 4500;

Вывод

+----+----------+-----+-----------+----------+
| ID | NAME     | AGE | ADDRESS   | SALARY   |
+----+----------+-----+-----------+----------+
|  2 | AndreyEx |  38 | Krasnodar | 55500.00 |
|  6 | Dima     |  32 | SP        | 45000.00 |
+----+----------+-----+-----------+----------+
2 rows in set (0.00 sec)

Редактор: AndreyEx