我有兩個查詢返回一個帶有計數的服務項目列表。一個用於整個數據庫,另一個用於特定的時間段。他們單獨工作,但我想優化他們到一個單一的查詢。結合來自同一來源的兩個計數查詢
這兩個查詢是:
SELECT service_type, count(service_type) from qba_customers group by service_type order by count(service_type) desc
SELECT service_type, count(service_type) from qba_customers WHERE created_on BETWEEN '2013-01-01' AND '2013-06-30' group by service_type order by count(service_type) desc
我嘗試了一些事情失敗,下面是我的想法最初將工作:提前
SELECT service_type, COUNT(service_type) AS full_count, (count(service_type) WHERE created_on BETWEEN '2013-01-01' AND '2013-06-30') AS period_count FROM qba_customers GROUP BY service_type ORDER BY service_type DESC
謝謝!
我試圖用的情況下,卻沒有足夠的 'THEN 1 END'。我讀了一些其他答案,並在發佈後的時刻找到了答案。非常感謝您的回答!我在合併/優化查詢方面很糟糕,今晚我還有更多事情要做,所以請留意! :d – Dizzy49