SQL z-score 구하기

SQL을 통해서 표준화점수 구하기

$$ z-score = \frac{X_i - Mean(X)}{std(X)} $$

Key : 평균, 표준편차는 하나의 값이니까, croos join으로 해결 group by 처럼 되면 안됨.

SELECT (T1.values - stats.average) / stats.s AS zvalue
FROM  [TABLE] T1 
CROSS JOIN
(SELECT sttdev(VALUES) AS s, avg(VALUES) AS average FROM [TABLE]) stats;

SQL, z-score, z점수, 표준화점수

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SQL z-score 구하기

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