Oracle转化为MySQL数据库
- 使用HttpClient调用Post方法的时候，EntityUtils.toString(response.getEntity()); 响应数据只能读取一次，读取多次会出现，Attempted read from closed stream错误。
- Oracle转化为MySQL数据库
| Oracle | MySQL |
| ORDER BY CREATED_TIME DESC NULLS LAST | ORDER BY CREATED_TIME DESC |
| NVL | IFNULL |
| TO_CHAR() | STR_TO_DATE |
| Select * from ( ) | Select * from ( ) tmp (别名不重复，便于查找) |
| TO_CHAR(CREATED_TIME,'YYYY-MM') | DATE_FORMAT(CREATED_TIME,'%Y-%m') |
| SELECT ROW_.*, ROWNUM ROWNUM_ FROM QUERYSQL | SELECT ROW_.*, ROW_NUMBER() OVER () AS ROWNUM_ FROM QUERYSQL |
| to_date(CREATETIME,'yyyy-MM-dd') | STR_TO_DATE(CREATETIME, '%Y-%m-%d') |
| add_months(‘2020-01-01’),+36) | DATE_ADD(STR_TO_DATE(‘2020-01-01’), INTERVAL 36 MONTH |
| ‘2025-01-01’ - sysdate | DATEDIFF(‘2025-01-01’), CURDATE()) |
| YEAR_MONTH | `YEAR_MONTH`(一种类型，keyword) |
| ROUND(a.total1 / NULLIF(b.total2, 0), 2) * 100 | FORMAT(ROUND(a.total1 / NULLIF(b.total2, 0), 2)*100,0) |
| TRUNC(total1/total2,2)*100 | FORMAT(ROUND(a.total1 / NULLIF(b.total2, 0), 2)*100,0) |
| SUPPLIERRANK||'级' | CONCAT(SUPPLIERRANK, '级') |
| SELECT TO_NUMBER('12345.67') FROM dual; | SELECT CAST('12345.67' AS DECIMAL(10, 2)); |
- 部署tomcat应用的时候，我们只需要将打包好的程序，放置在webapps路径下面即可，实现一个tomcat部署多个应用程序。通过，webapps下的包名作为路径，即可访问。其中，图片资源，尽量不要使用具体路径进行访问，这样会出现，资源访问不到的情况。使用<%=context%>作为主路径即可。