1.更改當前記錄以外的數據的xh自動加1（MySQL字段為int）
String sql = "UPDATE t_readtext as tr SET xh = xh +1\n" +"WHERE readcourceId <> "+ textbookId;
2.SQL CONCAT()函數作用是 返回的字符串參數連接的結果
工作的實例SQL代碼如下
SELECT b1.displayname , b1.englishname , a1.ztsj , a1.textcns FROM ( SELECT cc.yhid, MAX(cc.yhda) as yhda , cc.ztsj, COUNT(cc.textbookid) textcns FROM ( SELECT a.yhid, MAX(a.yhda) as yhda , CONCAT(FLOOR(a.ztsj /86400) , '天', FLOOR((a.ztsj /86400-FLOOR(a.ztsj /86400)) *24) , '時', FLOOR(a.ztsj %3600/60) , '分' ) as ztsj, a.textbookid from t_yhzt a INNER JOIN t_xslgclass b on b.xsid = a.yhid WHERE b.bjid = 44 AND a.createdt>= DATE_SUB(CURDATE(),INTERVAL dayofyear(now())-1 DAY) GROUP BY a.yhid, a.textbookid)cc GROUP BY cc.yhid )a1 INNER JOIN t_yh b1 on b1.id = a1.yhid limit 2

轉載于:https://www.cnblogs.com/jpfss/p/6814132.html

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