LeetCode 1693. Daily Leads and Partners

問題：取得每一天的Leads和Partners總數

解法：透過COUNT以及DISTINCT過濾重複的欄位值並計算總數，GROUP BY根據date_id和make_name欄位分組

SELECT date_id, make_name, COUNT(DISTINCT lead_id) AS unique_leads, COUNT(DISTINCT partner_id) AS unique_partners
FROM DailySales
GROUP BY date_id, make_name
ORDER BY date_id;