clause

choose two Which two statenents are tue about the COUNT function? A) It can only be used for NUMBER data types. B) COUNT (DISTINCT inv_amt) returns the number of rows excluding rows containing dupicates and NULLs in the INV_AMT column C) COUNT(*) returns the number of rows in a table including duplicate rows and rows containing NULLs in any column. D) A SELECT statement using the COUNT function with a DISTINCT keyword cannot have a WHERE clause. E) COUNT(inv_amt) returns the number of rows in a table including rows with NULL in the INV_AMT column. Answer：：BC (解析：count 对于 null 值是忽略的;可以与 where

Hi everybody I am trying to do this in CriteriaQuery, I was searching so long but I can't found anything to do it, someone can help me? SELECT b.name FROM Empl a LEFT OUTER JOIN Deplo b ON (a.id_depl = b.id_depl) AND b.id_place = 2; I'm just trying to do a condition in left join clause, I saw ".on" function but I don't know if it will work and how it work because I tried to do something like this: Join Table1, Table2j1 = root.join(Table1_.table2, JoinType.LEFT).on(cb.and(cb.equal(table2_.someid, someId))); But it need a boolean expresion. The on clause has been introduced in JPA 2.1. An

今天同事问了一个奇怪的MySQL group by问题。研究了一会发现饶有趣味，记录之~ 表结构简化如下： create table user ( id int not null primary key, remark varchar(20) null, constraint user_with_icp_remark_uindex unique (remark) ); 对上表执行如下 SELECT 操作： SELECT * FROM user GROUP BY remark; 会报错： SELECT list is not in GROUP BY clause and contains nonaggregated column 'user.id' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by 众所周知 MySQL 5.7 以后默认设置了 ONLY_FULL_GROUP_BY ，即默认设置下只允许 SELECT 的列：1）在GROUP BY中出现过；或 2）是聚合值。id 不满足上面的条件，出现异常很合理。但是对上表执行如下 SELECT 操作： SELECT * FROM user

对于知名容器厂商 Docker 公司来说昨天是一个值得铭记的日子。先是 Mirantis 宣布收购 Docker 企业级服务部门获得融资3500万美元。值得注意的是，这次收购并不包括 Docker Desktop 。据称， Mirantis 和 Docker 将共同开发核心的上游技术，为开源开发做出贡献。此外， Mirantis 和 Docker 将继续确保双方产品之间的集成， Docker 将专注于 Docker Desktop 和 Docker Hub ，而 Mirantis 专注于 Docker Enterprise 容器平台。几乎同时 Docker 还宣布公司已任命长期担任首席产品官的 Scott Johnston 为首席执行官（CEO）。 Johnston 是今年 Docker 的第三任 CEO ，接替 Rob Bearden ，而 Bearden 接替5月份卸任的 Steve Singh 。 在发布这则消息前，Docker公司已经融资2.7亿美元，是行业内的独角兽。 如今急匆匆贱卖其企业级业务令人吃惊。其实也不算贱卖。主要是 Docker 是开源的，从一开始面向的就是开发者，你要知道想从开发者手中赚钱是非常难的；而在赚钱的企业生产实践中缺乏行之有效的解决方案。互联网巨头 Google 开源（CNCF基金会） Kubernetes （k8s） 对其更是致命的打击

1. MySQL插入数据 语法： INSERT INTO table_name(field1,field2,field3,...fieldN) VALUES (value1,value2,value3,...valueN,) 如果数据是字符型，必须使用单引号或者是双引号，如"value"。 如： insert into student(username, age, sex, height) values("mengli", 26, 2, 165); 2. MySQL查询数据 2.1 语法：SELECT column_name,column_name FROM table_name [WHERE Clause] [LIMIT N][OFFSET M] 以下语句将取出学生表的全部记录： 如：select * from student; 有时取出所有信息数据量太大，浪费内存。比如只想查询所有同学的名字，则可以指定要查询的字段： SELECT username FROM student; 2.2. DISTINCT 关键字 使用DISTINCT关键字 可以指定某一列或者多列不重复 ，语法为：SELECT DISTINCT fields FROM table_name， 这样一来紧跟在DISTINCT后面的列将 排重后 显示出来，优先保留排在前面的行。 如：SELECT DISTINCT

I got this problem with Group_Concat and a where filter. In my table i got module names which are linked to a client. I want to search clients by module name, but in the group concat i still want to see all modules that are owned by the client. currently it will display all clients with those modules, but it will only display that specific module. I can't figure out how to make them both work together. Any suggestions on how to get my expected result?? These are some basic tables and the query i tried along with results i get and the result i really wanted Client +--------------------+ | id |

Choose three Which three actions can you perfom only with system privileges? A) Truncate a table in another schema. B) Access flat files via a database, which are stored in an operating system directory. C) Log in to a database. D) Query any table in a database. E) Use the WITH GRANT OPTION clause. F) Execute a procedure in another schema. Answer：CDF (解析：这道题考的就是可以授权哪些系统权限去做哪些活儿。 C：create session D：select any table F：EXECUTE ANY PROCEDURE 原来以为 AAnswer：正确，结构查询发现没有 truncate any table 的权限。 ) 来源： https://my.oschina.net/u/3902946/blog/3128196