MySQL の WHERE

SELECT COLUMN_LIST
FROM TABLE_NAME
WHERE SEARCH_CONDITION;

SELECT film_id, title, rating
FROM film
WHERE rating = 'G'
ORDER BY title
LIMIT 5;

+---------+-------------------+--------+
| film_id | title             | rating |
+---------+-------------------+--------+
|       2 | ACE GOLDFINGER    | G      |
|       4 | AFFAIR PREJUDICE  | G      |
|       5 | AFRICAN EGG       | G      |
|      11 | ALAMO VIDEOTAPE   | G      |
|      22 | AMISTAD MIDSUMMER | G      |
+---------+-------------------+--------+
5 rows in set (0.00 sec)

SELECT title, length
FROM film
WHERE length > 180
ORDER BY length DESC, title
LIMIT 5;

+----------------+--------+
| title          | length |
+----------------+--------+
| CHICAGO NORTH  |    185 |
| CONTROL ANTHEM |    185 |
| DARN FORRESTER |    185 |
| GANGS PRIDE    |    185 |
| HOME PITY      |    185 |
+----------------+--------+
5 rows in set (0.00 sec)

SELECT title
FROM film
WHERE rental_rate = 4.99
ORDER BY title
LIMIT 5;

+------------------+
| title            |
+------------------+
| ACE GOLDFINGER   |
| AIRPLANE SIERRA  |
| AIRPORT POLLOCK  |
| ALADDIN CALENDAR |
| ALI FOREVER      |
+------------------+
5 rows in set (0.00 sec)

SELECT title, rating
FROM film
WHERE rating <> 'G'
ORDER BY title
LIMIT 5;

+------------------+--------+
| title            | rating |
+------------------+--------+
| ACADEMY DINOSAUR | PG     |
| ADAPTATION HOLES | NC-17  |
| AGENT TRUMAN     | PG     |
| AIRPLANE SIERRA  | PG-13  |
| AIRPORT POLLOCK  | R      |
+------------------+--------+
5 rows in set (0.00 sec)

SELECT title, rental_rate * 2 AS double_rate
FROM film
WHERE double_rate > 8
ORDER BY title;

ERROR 1054 (42S22): Unknown column 'double_rate' in 'where clause'

SELECT title, rental_rate * 2 AS double_rate
FROM film
WHERE rental_rate * 2 > 8
ORDER BY title
LIMIT 5;

+------------------+-------------+
| title            | double_rate |
+------------------+-------------+
| ACE GOLDFINGER   |        9.98 |
| AIRPLANE SIERRA  |        9.98 |
| AIRPORT POLLOCK  |        9.98 |
| ALADDIN CALENDAR |        9.98 |
| ALI FOREVER      |        9.98 |
+------------------+-------------+
5 rows in set (0.00 sec)

SELECT title FROM film WHERE rating = 'X';

Empty set (0.00 sec)