ters. RESULTS[RaceName, Year, Place, AthleteName] (RaceName, Year, Place) form the primary key. (RaceName, Year) form a foreign key referencing RACES. RECORDS[RaceName, Year, Record, Time] (RaceName, Year, Record) form the primary key. The foreign key is the same as for RESULTS. The values of Record
SQL
SQL stands for Structured Query Language, is a form of communication that uses queries structured in a specific format to store, manage & retrieve data from a relational database.
Queries
A query is a type of computer programming language that is used to retrieve data from a database. Databases are useful in a variety of ways. They enable the retrieval of records or parts of records, as well as the performance of various calculations prior to displaying the results. A search query is one type of query that many people perform several times per day. A search query is executed every time you use a search engine to find something. When you press the Enter key, the keywords are sent to the search engine, where they are processed by an algorithm that retrieves related results from the search index. Your query's results are displayed on a search engine results page, or SER.
Consider a
RESULTS[RaceName, Year, Place, AthleteName] (RaceName, Year, Place) form the primary key. (RaceName, Year) form a foreign key referencing RACES.
RECORDS[RaceName, Year, Record, Time] (RaceName, Year, Record) form the primary key. The foreign key is the same as for RESULTS. The values of Record could be, e.g., World Record, National Record, Fastest Time. Time is in seconds.
Write queries in SQL that produce the answers to the following questions:
(a) Find the names of all athletes who exclusively participate in runs that are longer than 40 kilometers.
(b) Find organizers who organized a mountain-bike and a bike race, where the mountain-bike race was longer than the bike race.
(c) Find the names of all athletes who achieved a world record in runs of (Distance=) 10000m.
(d) List all triathlons where a world record was set before 1995 and after 2005.
(e) Find all pairs of races (r1, r2) where the same type of record was broken.
(f) Find the names of all athletes who have participated in races in at least two different countries.
(g) Find the record category for which the average of records over the distance of 21100m has the lowest average time
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