卑微的码农

【代码】日期字段按年、月查询sql。

SELECT a.experience_name AS "experienceName" ,b.experience_type_name as "experienceTypeName" ,c.user_name as "userName" ,d.dept_name as "deptName" FROM experience a left join experience_type ...

package com.util;import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Date;import java.util.UUID;/** * 描述: Twitter的分布式自增ID雪花算法snowflake (Java版) **/public class IdUtil { /** * 起始的时间戳 */ private fina.

where instr(user_name, "石") > 0

SELECT temp.USERID AS "userId",di.DUTYNAME AS "dutyName"FROM (SELECT u.USERID，u.DUTYIDFROMuserinfo uwhere) temp LEFT JOIN DUTYINFO di ON temp.DUTYID=di.DUTYID;

BasePersonInfo.javapublic class BasePersonInfo extends BaseEntity implements Serializable,Cloneable{ /** 人员ID */ private Integer personId ; /** 姓名 */ private String personName ; ...

SELECT D.DEPTID,D.DEPTNAME,D.DEPTPARENTID,D1.DEPTNAME AS DEPTPARENTNAME,D.DEPTCODE,D.CURRENTNUM,D.DEPTPREDICTNNT,D.CREATDATETIME,D.DESCRIBE,D.COMPINFOID,C.COMPINFONAME FROM DEPARTMENT D,COMPANYINFO C,DEPARTMENT D1 WHERE D.COMPINFOID=C.COMPINFOID AND D.D.

[mysqld]# 设置端口port=3306# 设置mysql的安装目录basedir=D:\\javaTools\\mysql-8.0.17-winx64 # 切记此处一定要用双斜杠\\，单斜杠我这里会出错，不过看别人的教程，有的是单斜杠。自己尝试吧# 设置mysql数据库的数据的存放目录datadir=D:\\javaTools\\mysql-8.0.17-winx64\\...

cmd进入mysql ：D:\javaTools\mysql-8.0.17-winx64\bin>mysql -u root -p输入密码：D:\javaTools\mysql-8.0.17-winx64\bin>mysql -u root -pEnter password: **********Welcome to the MySQL monitor. Co...

数据库存的路径用“/”String dir = new File("").getCanonicalPath();String filepath = dir+"/archive/src/main/webapp/userfiles/fileupload/"+DateUtils.getCurrentDate("yyyyMM")+"/";filepath=StringUtils.replace(...

文本编辑器notpad：word文档：

CREATE table edoc.log_archive like thams.log_archive;

https://www.cnblogs.com/ParanoiaApe/p/9005266.htmlselect column_name,data_type from information_schema.columns where table_schema='database_name' and table_name='table_name';

SELECT * FROM s_fieldassodetail WHERE fieldasso=1564381047325600343;SELECT * FROM s_archive_field WHERE tableid="f1_2_document";按照 s_archive_field 表为主查询字段 code 和s_fieldassodetail 表字段targ...

安装：mysqld --install [mysql-5.7.27-1]mysqld --initialize-insecurenet start [mysql-5.7.27-1]打开注册表，找到HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\,修改ImagePath参数，更正服务相关路径。卸载：mysqld --...

1、where 及 order by 涉及的列上建立索引；2、between、exists代替 in；3、union all 代替 or；4、避免使用 != 或 <> 操作符；5、不使用 is null；6、不要使用 *；7、。。。...

1、在SQL语句中经常进行GROUP BY、ORDER BY的字段上建立索引；2、在不同值较少较多的字段上不必要建立索引；3、对于经常存取的列避免建立索引；4、用于联接的列（主健/外健）上建立索引；...

a表：person_id persion_name 1 aa 2 bb 3 cc b表：job_id job_name parent_id 1 11 1 2 22 2 3 33 4 1) 内连接（join=inner join）显示连接：SELECT a.*,b.* ...