mysql中將null值轉換為0的語句

復制代碼 代碼如下:
SELECT
IF(AVG(cai.conversionsRate) IS NULL,0,AVG(cai.conversionsRate))
AS conversionsRate
FROM campaign_info cai
WHERE insertTime BETWEEN '2011-02-01' AND '2011-02-04' AND googleCampaignId=23331401