MYSQL-如何顯示0沒有結果？

Question

我有下面的查詢，它工作正常，並在儀表板上顯示任何未接來電。 但是，如果沒有結果，則不返回任何數據。 如何顯示“ 0”沒有結果？ 謝謝

SELECT DialledNumber, COUNT(*) As Missed
FROM CALLS
WHERE destination like '%!%' AND datetime BETWEEN CURDATE() AND DATE_ADD(CURDATE(), INTERVAL 1 day)
GROUP By DialledNumber
HAVING (DialledNumber = '500') OR (DialledNumber = '580') OR (DialledNumber = '515') OR (DialledNumber = '513') OR (DialledNumber = '514')

Answer 1

您可以在MYSQL中使用IFNULL函數

SELECT DialledNumber, IFNULL(COUNT(DialledNumber),0) As Missed
FROM CALLS
WHERE destination like '%!%' AND datetime BETWEEN CURDATE() AND DATE_ADD(CURDATE(), INTERVAL 1 day)
GROUP By DialledNumber
HAVING (DialledNumber = '500') OR (DialledNumber = '580') OR (DialledNumber = '515') OR (DialledNumber = '513') OR (DialledNumber = '514')

Answer 2

你想使用left join ，而不是in ：

SELECT dn.dn, COUNT(c.diallednumber) As Missed
FROM (select '500' as dn union all select '580' union all select '515' union all
      select '513' union all select '514'
     ) dn left join
     CALLS c
     ON c.diallednumber = dn.dn and
        c.destination like '%!%' AND
        c.datetime BETWEEN CURDATE() AND DATE_ADD(CURDATE(), INTERVAL 1 day)
GROUP By dn.dn;

需注意的是，英語中的“撥號”沒有兩個“ l”。

Answer 3

這可能對您有用（未試用）：

SELECT CALLS.DialedNumber, IFNULL(MISSEDCALLS.Missed, 0) FROM CALLS
LEFT JOIN (
  SELECT DialedNumber, COUNT(*) As Missed FROM CALLS
  WHERE destination like '%!%' AND datetime BETWEEN CURDATE() AND DATE_ADD(CURDATE(), INTERVAL 1 day) 
  GROUP By DialledNumber
) AS MISSEDCALLS ON MISSEDCALLS.DialedNumber = CALLS.DialedNumber
WHERE CALLS.DialledNumber IN ('500', '580', '515', '513', '514')