Aggregate

VARIANCE

PostgreSQL

Menghitung varians dari sekumpulan nilai. VARIANCE dan VAR_SAMP menggunakan sample variance (n-1). VAR_POP menggunakan population variance (n). Varians adalah kuadrat dari standar deviasi.

Tipe hasil: double precision

Syntax

SQL

VARIANCE(expression)
VAR_SAMP(expression)
VAR_POP(expression)

Parameter

expressionnumericwajib

Kolom numerik yang akan dihitung variansnya

Contoh Penggunaan

Varians Sederhana

SQL

1 SELECT 
2   VARIANCE(price) AS price_variance,
3   STDDEV(price) AS price_stddev,
4   SQRT(VARIANCE(price)) AS calculated_stddev
5 FROM products;

Varians dan hubungannya dengan standar deviasi.

Hasil

price_variance	price_stddev	calculated_stddev
625000000	25000	25000

Analisis Risiko Investasi

SQL

1 SELECT 
2   stock_symbol,
3   AVG(daily_return) AS avg_return,
4   VARIANCE(daily_return) AS return_variance
5 FROM stock_prices
6 GROUP BY stock_symbol
7 ORDER BY return_variance;

Menganalisis volatilitas saham berdasarkan varians return.

Hasil

stock_symbol	avg_return	return_variance
BBCA	0.001	0.000025
GOTO	0.002	0.000156

Sample vs Population Variance

SQL

1 SELECT 
2   VAR_SAMP(score) AS sample_variance,
3   VAR_POP(score) AS pop_variance
4 FROM exam_scores;

Perbandingan sample dan population variance.

Fungsi Equivalen di Database Lain

VARIANCE

MySQL

VARIANCE

Snowflake

VARIANCE

BigQuery

VARIANCE

DuckDB

Fungsi Terkait

STDDEVCORRCOVAR_POPCOVAR_SAMPPERCENTILE_CONTPERCENTILE_DISCMODE

Kembali ke PostgreSQL Functions

1	SELECT
2	VARIANCE(price) AS price_variance,
3	STDDEV(price) AS price_stddev,
4	SQRT(VARIANCE(price)) AS calculated_stddev
5	FROM products;

1	SELECT
2	stock_symbol,
3	AVG(daily_return) AS avg_return,
4	VARIANCE(daily_return) AS return_variance
5	FROM stock_prices
6	GROUP BY stock_symbol
7	ORDER BY return_variance;

1	SELECT
2	VAR_SAMP(score) AS sample_variance,
3	VAR_POP(score) AS pop_variance
4	FROM exam_scores;