--更新时间2023.11.26 21:30 负责人:jerrysuse DBAliCMSIF EXISTS (select * from sysobjects where namehkcms_user)--判断是否存在此表DROP TABLE hkcms_user
CREATE TABLE hkcms_user (id int primary key identity(1, 1),username char(32) NOT N…
Redis是优秀的非关系型数据库,源码中的链表是很经典,将其提取使用
/* adlist.c - A generic doubly linked list implementation** Copyright (c) 2006-2010, Salvatore Sanfilippo <antirez at gmail dot com>* All rights reserved.** Redistri…
1.GROUP BY GROUP BY 函数就是 SQL 中用来实现分组的函数,其用于结合聚合函数,能根据给定数据列的每个成员对查询结果进行分组统计,最终得到一个分组汇总表。
mysql> SELECT country, COUNT(country) AS teacher_count-> FROM teacher…