53 perintah SQL, lengkap dengan query dan hasilnya.

WITH urut AS (
  SELECT kategori, produk, qty * harga AS omzet,
         ROW_NUMBER() OVER (PARTITION BY kategori ORDER BY qty * harga DESC) AS rn
  FROM penjualan
)
SELECT kategori, produk, omzet FROM urut WHERE rn = 1;

SELECT produk, COUNT(*) AS jumlah
FROM penjualan
GROUP BY produk
HAVING COUNT(*) > 1;

SELECT kategori,
       SUM(qty * harga) AS omzet,
       ROUND(100.0 * SUM(qty * harga) / SUM(SUM(qty * harga)) OVER (), 1) AS persen
FROM penjualan
GROUP BY kategori;

SELECT d.nama_dept
FROM departemen AS d
LEFT JOIN karyawan AS k ON k.dept_id = d.id
WHERE k.id IS NULL;

SELECT COUNT(*) AS total,
       SUM(CASE WHEN kota = 'Jakarta' THEN 1 ELSE 0 END) AS di_jakarta,
       SUM(CASE WHEN gaji >= 10000000 THEN 1 ELSE 0 END) AS gaji_10jt
FROM karyawan;

WITH b AS (
  SELECT SUBSTRING(tanggal, 1, 7) AS bulan, SUM(qty * harga) AS omzet
  FROM penjualan GROUP BY 1
)
SELECT bulan, omzet,
       ROUND(100.0 * (omzet - LAG(omzet) OVER (ORDER BY bulan))
             / NULLIF(LAG(omzet) OVER (ORDER BY bulan), 0), 1) AS growth_persen
FROM b;