[作业] Sql (二)

Weather Observation Station 1

Query a list of CITY and STATE from the STATION table.

Input Format

The STATION table is described as follows:

where LAT_N is the northern latitude and LONG_W is the western longitude.

SELECT CITY,STATE FROM STATION;

Weather Observation Station 2

Query a list of CITY names from STATION with even ID numbers only. You may print the results in any order, but must exclude duplicates from your answer.

Input Format

The STATION table is described as follows:

where LAT_N is the northern latitude and LONG_W is the western longitude.

select distinct city from station where (id % 2) = 0;

Weather Observation Station 4

Let  N be the number of CITY entries in STATION, and let N  be the number of  N - N distinct CITY names in STATION; query the value of  from STATION. In other words, find the difference between the total number of CITY entries in the table and the number of distinct CITY entries in the table.

Input Format

The STATION table is described as follows:

where LAT_N is the northern latitude and LONG_W is the western longitude.

SELECT (COUNT(CITY) - COUNT(DISTINCT CITY)) FROM STATION;

Weather Observation Station 5

Query the two cities in STATION with the shortest and longest CITY names, as well as their respective lengths (i.e.: number of characters in the name). If there is more than one smallest or largest city, choose the one that comes first when ordered alphabetically.

Input Format

The STATION table is described as follows:

where LAT_N is the northern latitude and LONG_W is the western longitude.

Sample Input

Let's say that CITY only has four entries: DEF, ABC, PQRS and WXY

Sample Output

ABC 3
PQRS 4

Explanation

When ordered alphabetically, the CITY names are listed as ABC, DEF, PQRS, and WXY, with the respective lengths  3, 3, 4 and 3 . The longest-named city is obviously PQRS, but there are 3 options for shortest-named city; we choose ABC, because it comes first alphabetically.

Note 
You can write two separate queries to get the desired output. It need not be a single query.

SELECT CITY, CHAR_LENGTH(CITY) FROM STATION ORDER BY CHAR_LENGTH(CITY), CITY LIMIT 1;
SELECT CITY, CHAR_LENGTH(CITY) FROM STATION ORDER BY CHAR_LENGTH(CITY) DESC, CITY LIMIT 1;

Weather Observation Station 6

Query the list of CITY names starting with vowels (i.e., a, e, i, o, or u) from STATION. Your result cannot contain duplicates.

Input Format

The STATION table is described as follows:

where LAT_N is the northern latitude and LONG_W is the western longitude.

SELECT DISTINCT city FROM station WHERE city REGEXP "^[aeiou].*";

Weather Observation Station 7

Query the list of CITY names ending with vowels (a, e, i, o, u) from STATION. Your result cannot contain duplicates.

Input Format

The STATION table is described as follows:

where LAT_N is the northern latitude and LONG_W is the western longitude.

SELECT DISTINCT CITY FROM STATION WHERE LOWER(SUBSTR(CITY,LENGTH(CITY),1)) IN ('a','e','i','o','u');

Weather Observation Station 8

Query the list of CITY names from STATION which have vowels (i.e., a, e, i, o, and u) as both their first and last characters. Your result cannot contain duplicates.

Input Format

The STATION table is described as follows:

where LAT_N is the northern latitude and LONG_W is the western longitude.

select distinct city from station 
where left(city,1) in ('a','e','i','o','u') 
and right(city, 1) in ('a','e','i','o','u')

Weather Observation Station 9

Query the list of CITY names from STATION that do not start with vowels. Your result cannot contain duplicates.

Input Format

The STATION table is described as follows:

where LAT_N is the northern latitude and LONG_W is the western longitude.

SELECT DISTINCT CITY FROM STATION
WHERE CITY REGEXP '^[^aeiou]';

Weather Observation Station 10

Query the list of CITY names from STATION that do not end with vowels. Your result cannot contain duplicates.

Input Format

The STATION table is described as follows:

where LAT_N is the northern latitude and LONG_W is the western longitude.

SELECT DISTINCT CITY FROM STATION WHERE CITY REGEXP '[^AEIOU]$';

Weather Observation Station 11

Query the list of CITY names from STATION that either do not start with vowels or do not end with vowels. Your result cannot contain duplicates.

Input Format

The STATION table is described as follows:

where LAT_N is the northern latitude and LONG_W is the western longitude.

SELECT DISTINCT CITY FROM STATION WHERE CITY NOT RLIKE '^[aeiouAEIOU].*.[aeiouAEIOU]$';

Weather Observation Station 12

Query the list of CITY names from STATION that do not start with vowels and do not end with vowels. Your result cannot contain duplicates.

Input Format

The STATION table is described as follows:

where LAT_N is the northern latitude and LONG_W is the western longitude.

   select distinct city from station where city regexp '^[^aeiou].*[^aeiou]$'