Using SUM, Count, MAX, DISTINCT and ORDER BY/ja
| Language: | English • 日本語 |
|---|
BBCテーブルの国のプロフィール
集計
関数 SUM, COUNT, MAX, AVG を数値フィールド（属性）に適用すると1行に集計した結果を返す。
(これらの関数は GROUP BY 節で用いるとさらに便利)
Distinct
SELECT のデフォルトの結果は重複した行を含んでいてもよい。
DISTINCT キーワードを加えることで重複を取り除くことが出来る。
Order by
ORDER BY は SELECT の結果を特定の順序で並べ替える。ASC または DESC キーワードで 昇順（最小が先頭、最大が末尾）または降順になる。
ヨーロッパの人口population と GDP を集計する。
SELECT SUM(population), SUM(gdp)
FROM bbc
WHERE region = 'Europe'
SELECT SUM(population), SUM(gdp)
FROM bbc
WHERE region = 'Europe'
どんな地域が有るか？
SELECT DISTINCT region FROM bbc
SELECT DISTINCT region FROM bbc
人口が100000000人より大きな各国のname と populationを人口の多い順に表示する
SELECT name, population
FROM bbc
WHERE population > 100000000
ORDER BY population DESC
SELECT name, population
FROM bbc
WHERE population > 100000000
ORDER BY population DESC
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