Quick Ref.

The Table Tennis Olympics Database

The table ttms shows the Olympic medal winners for Table Tennis (Men's Singles). The country of each winner is given by a three letter code. To get the actual country name you must JOIN this table to the country table.
The two tables country and ttms are ONE TO MANY. One country has many winners, each winner has only one country.
ttms
games color who country
1988 gold Yoo Nam-Kyu KOR
1988 silver Kim Ki Taik KOR
........
country
id name
ALG Algeria
ARG Argentina
... ...
KOR Korea
....

How to do joins.

The phrase FROM ttms JOIN country ON ttms.country=country.id represents the join of the tables ttms and country. This JOIN has one row for every medal winner. In addition to the ttms fields (games, color, who and country) it includes the details of the corresponding country (id, name ).

1a. Show the athelete (who) and the country name for medal winners in 2000.
ttms(games, color, who, country)
country(id, name)
Results
1b. Show the who and the color of the medal for the medal winners from 'Sweden'.
ttms(games, color, who, country)
country(id, name)
Results
1c. Show the years in which 'China' won a 'gold' medal.
ttms(games, color, who, country)
country(id, name)
Results

Women's Singles Table Tennis Olympics Database

The Summer Olympic games are held every four years in a different city. The table games shows which city the games were held in. The Women's Single's winners are in the table ttws.
ttws
games color who country
1988 gold Jing Chen CHN
1988 silver Li Hui-Fen CHN
........
games
yr city country
1988 Seoul KOR
1992 Barcelona ESP
......
2a. Show who won medals in the 'Barcelona' games.
ttws(games, color, who, country)
games(yr, city, country)
Results
2b. Show which city 'Jing Chen' won medals. Show the city and the medal color.
ttws(games, color, who, country)
games(yr, city, country)
Results
2c. Show who won the gold medal and the city.
ttws(games, color, who, country)
games(yr, city, country)
Results

Table Tennis Mens Doubles

The Table Tennis Mens Double teams are stored in the table team. Each team has an arbitrary number that is referenced from the table ttmd.
ttmd
games color team country
1988 gold 1 CHN
1988 silver 2 YUG
.. .. .. ..
team
id name
1 Long-Can Chen
1 Qing-Guang Wei
2 Ilija Lupulesku
2 Zoran Primorac
.. ..
3a. Show the games and color of the medal won by the team that includes 'Yan Sen'.
ttmd(games, color, team, country)
team(id, name)
Results
3b. Show the 'gold' medal winners in 2004.
ttmd(games, color, team, country)
team(id, name)
Results
3c. Show the name of each medal winner country 'FRA'.
ttmd(games, color, team, country)
team(id, name)
Results

The next tutorial about the Movie database involves some slightly more complicated joins.