Hari 11: COUNT, SUM, AVG, MIN, MAX

Fungsi Agregat

Fungsi agregat meringkas banyak baris menjadi satu nilai.

-- COUNT — hitung jumlah baris
SELECT COUNT(*) AS total_pelanggan FROM pelanggan;
SELECT COUNT(email) AS pelanggan_punya_email FROM pelanggan; -- NULL tidak dihitung

-- SUM — total nilai
SELECT SUM(total_harga) AS total_pendapatan FROM pesanan;

-- AVG — rata-rata
SELECT AVG(umur) AS rata_umur FROM pelanggan;
SELECT ROUND(AVG(harga), 0) AS rata_harga_produk FROM produk;

-- MIN / MAX — nilai terkecil/terbesar
SELECT MIN(harga) AS termurah, MAX(harga) AS termahal FROM produk;

-- Kombinasi dalam satu query
SELECT
  COUNT(*) AS jumlah_produk,
  SUM(stok) AS total_stok,
  ROUND(AVG(harga), 0) AS rata_harga,
  MIN(harga) AS termurah,
  MAX(harga) AS termahal
FROM produk;