Question

我有這樣的MySQL查詢....

"SELECT 
SUM(CASE WHEN ticket_source='bpt' THEN tix_tickets.ticket_price END) AS bpt_money, 
COUNT(CASE WHEN ticket_source='bpt' THEN 1 END) AS bpt_num, 
SUM(CASE WHEN ticket_source='door' THEN tix_tickets.ticket_price END) AS door_money, 
COUNT(CASE WHEN ticket_source='door' THEN 1 END) AS door_num, 
SUM(CASE WHEN ticket_source='goldstar' THEN tix_tickets.ticket_price END) AS goldstar_money, 
COUNT(CASE WHEN ticket_source='goldstar' THEN 1 END) AS goldstar_num, 
COUNT(CASE WHEN ticket_price='0' THEN 1 END) AS free_tix, 
COUNT(CASE WHEN ticket_price='10' THEN 1 END) AS ten_buck_tix, 
COUNT(CASE WHEN ticket_price='20' THEN 1 END) AS twenty_buck_tix, 
COUNT(CASE WHEN ticket_price='25' THEN 1 END) AS twentyfive_buck_tix 
FROM tix_people,tix_tickets WHERE tix_people.ID=tix_tickets.holder_id GROUP BY ticket_date ORDER BY ticket_date" 

它的偉大工程，但我想在表中使用的每ticket_price而無需分別打電話給他們。我希望每個ticket_source都不需要單獨調用。我想我可以縮短我的代碼，現在做的更好，因爲我擴大了來源和價格的數量。

Answer 1

你必須寫出你想要選擇的列。如果你想嘗試建立一個查詢，你可以這樣做。這裏是你的選擇的一個小重構。我清理了一些case語句只是使用布爾和

SELECT 
    SUM(CASE WHEN ticket_source='bpt' THEN tix_tickets.ticket_price END) AS bpt_money, 
    SUM(ticket_source='bpt') AS bpt_num, 
    SUM(CASE WHEN ticket_source='door' THEN tix_tickets.ticket_price END) AS door_money, 
    SUM(ticket_source='door') AS door_num, 
    SUM(CASE WHEN ticket_source='goldstar' THEN tix_tickets.ticket_price END) AS goldstar_money, 
    SUM(ticket_source='goldstar') AS goldstar_num, 
    SUM(ticket_price='0') AS free_tix, 
    SUM(ticket_price='10') AS ten_buck_tix, 
    SUM(ticket_price='20') AS twenty_buck_tix, 
    SUM(ticket_price='25') AS twentyfive_buck_tix 
FROM tix_people 
JOIN tix_tickets on tix_people.ID=tix_tickets.holder_id 
GROUP BY ticket_date 
ORDER BY ticket_date