轉換相關的MySQL子查詢noncorelated

Question

我需要幫助相關子查詢轉換成非相關，這是一個查詢：

http://sqlfiddle.com/#!2/2a67b/3

感謝意見

Answer 1

我真的很努力工作了什麼你的SQL試圖擺在首位。

它似乎是在最小和最大秒之間（好的，比最大日期時間多1秒）獲得每秒鐘的時間，並獲得記錄的數量。

如果是這樣，那麼最多〜1000秒應對： -

SELECT ADDDATE(MinCallDate, INTERVAL Sub1.i SECOND) AS aDate, COUNT(*) 
FROM 
(
    SELECT MIN(calldate) AS MinCallDate, MAX(calldate) AS MaxCallDate 
    FROM calls 
)Sub0 
CROSS JOIN 
(
    SELECT units.i + tens.i * 10 + hundreds.i * 100 as i 
    FROM (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) units 
    CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) tens 
    CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) hundreds 
) Sub1 
INNER JOIN 
(
    SELECT calldate, ADDDATE(calldate, INTERVAL billsec SECOND) AS callenddate 
    FROM calls 
) b 
ON DATE_FORMAT(ADDDATE('2013-05-14 09:40:30', INTERVAL Sub1.i SECOND),"%Y%m%d%H%i%s") BETWEEN b.calldate AND b.callenddate 
WHERE ADDDATE(MinCallDate, INTERVAL Sub1.i SECOND) <= MaxCallDate 
AND Sub1.i < TIMESTAMPDIFF(SECOND,'2013-05-14 09:40:30', '2013-05-14 09:41:00') 
GROUP BY aDate 

如果你能提供你正在努力實現我也許能拿出更好的東西什麼的非SQL解釋。

編輯 - 很簡單的計數： -

SELECT Sub1.TimeSecond, COUNT(Sub2.CallSecond) 
FROM 
(
    SELECT ADDDATE('2013-05-14 09:40:30', INTERVAL units.i + tens.i * 10 + hundreds.i * 100 + thousands.i * 1000 SECOND) AS TimeSecond 
    FROM (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) units 
    CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) tens 
    CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) hundreds 
    CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) thousands 
    HAVING TimeSecond BETWEEN '2013-05-14 09:40:30' AND '2013-05-14 09:41:00' 
) Sub1 
LEFT OUTER JOIN 
(
    SELECT ADDDATE(calldate, INTERVAL units.i + tens.i * 10 + hundreds.i * 100 + thousands.i * 1000 SECOND) AS CallSecond 
    FROM calls 
    CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) units 
    CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) tens 
    CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) hundreds 
    CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) thousands 
    WHERE units.i + tens.i * 10 + hundreds.i * 100 + thousands.i * 1000 <= billsec 
) Sub2 
ON Sub1.TimeSecond = Sub2.CallSecond 
GROUP BY Sub1.TimeSecond 

這將應付的範圍/手機通話9999秒（易於擴展它更大的範圍內，但會使其速度較慢但不能肯定。所有這些都將是有效，因爲MySQL不能真正使用索引的任何連接

簡單

會是這樣，因爲它不是每個通話時長中產生，每次： - 。

SELECT Sub1.TimeSecond, COUNT(calls.calldate) 
FROM 
(
    SELECT ADDDATE('2013-05-14 09:40:30', INTERVAL units.i + tens.i * 10 + hundreds.i * 100 + thousands.i * 1000 SECOND) AS TimeSecond 
    FROM (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) units 
    CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) tens 
    CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) hundreds 
    CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) thousands 
    HAVING TimeSecond BETWEEN '2013-05-14 09:40:30' AND '2013-05-14 09:41:00' 
) Sub1 
LEFT OUTER JOIN calls 
ON Sub1.TimeSecond BETWEEN calls.calldate AND ADDDATE(calls.calldate, INTERVAL calls.billsec SECOND) 
GROUP BY Sub1.TimeSecond 

你可以改變表格的佈局嗎？如果是這樣，爲呼叫結束日期時間添加一列可能會有所幫助。