我正在用10個問題創建一個調查。所有問題都有5個可能的答案,其值爲1-5。數據存儲在每個用戶一行的數據庫中。每個問題都有一個答案。優化SQL查詢以獲得特定答案的計數
爲了使條形圖的回答每一個問題,我目前檢索的行數,其中一個特定列的值等於一個特定的可能的答案:
SELECT COUNT(*) AS `records_found` FROM (`antworten`) WHERE `frage1` = 1
SELECT COUNT(*) AS `records_found` FROM (`antworten`) WHERE `frage1` = 2
SELECT COUNT(*) AS `records_found` FROM (`antworten`) WHERE `frage1` = 3
SELECT COUNT(*) AS `records_found` FROM (`antworten`) WHERE `frage1` = 4
SELECT COUNT(*) AS `records_found` FROM (`antworten`) WHERE `frage1` = 5
SELECT COUNT(*) AS `records_found` FROM (`antworten`) WHERE `frage2` = 1
SELECT COUNT(*) AS `records_found` FROM (`antworten`) WHERE `frage2` = 2
SELECT COUNT(*) AS `records_found` FROM (`antworten`) WHERE `frage2` = 3
SELECT COUNT(*) AS `records_found` FROM (`antworten`) WHERE `frage2` = 4
SELECT COUNT(*) AS `records_found` FROM (`antworten`) WHERE `frage2` = 5
(...)
這將生成如下圖形:http://i.imgur.com/SESJ8.png
這可能很愚蠢,並且可能有更好的方法來檢索所需的數據。我無法想出它,有人可以幫助我嗎? :) 謝謝。
是的,我認爲它必須像這樣+1 – Unreason 2010-07-01 09:48:21
這看起來不錯!是否也可以爲每個可能的答案設置Anzahl = 0而不返回結果? – 2010-07-01 09:51:36
@danilo,這是免費的 - 空集*的計數(*)*等於0. – Unreason 2010-07-01 09:53:10