learning sql o reilly

management of viewsBecause many of the company's daily work is regular, if you introduce some view mechanism, it will greatly improve work efficiency.Create a ViewCreate a high-priced view of the goods, show all the price of more than 4000 yuan in the name of the product, brand and price/* Switch to the database */use sales Management go/* Create a View */create view high price commodity _viewasselect product name, brand, price from commodity table where price >4000goWorking with viewsSee the n

SQL statement learning, SQL statements Exercise for one table 1. Create a table create table student(name Char(20),curriculum Char(20),score Char(20)); Insert data: Insert into student (name, curriculum, score) VALUES ('wang wu', 'mat', '123 '); Mysql> select * from student; + -------- + ------------ + ------- + | Name | curriculum | score | + -------- + ---

Tags: rgb alter des post border SAN Delete table SQL statement mysq To Create a database: CREATE DATABASE stefan; To Delete a database: DROP DATABASE stefan; To rename a database: there is no direct way to rename a database. methods that are no longer used: RENAME DATABASE stefan TO LCDB; To Create a table syntax: CREATE TABLE 表名称 ( 列名称1 数据类型, 列名称2 数据类型, 列名称3 数据类型, .... ) To view a table structure: DESCRIBE Persons; The ALTER table statement i

Oracle SQL advanced programming learning notes (I) Core SQL statement 1, select statement execution sequence 5 SELECT (1) first execute the clause or link clause after the From clause to query the initial dataset. (2) execute the where clause to streamline the initial result set, query the dataset that meets the where condition from the initial dataset. (3) ex

SQL-database materials used for basic learning, SQL-basic database materials -------------------------- Create MERs table------------------------Create table MERs(Cust_id char (10) not null,Cust_name char (50) not null,Cust_address char (50) NULL,Cust_city char (50) NULL,Cust_state char (5) NULL,Cust_zip char (10) NULL,Cust_country char (50) NULL,Cust_contact ch

Tags: query modify name hang database Type table name View ESCTake MySQL as an exampleCommon operations on a databaseCreating a database: Create databases mydb;Delete databases: drop database mydb;Switch database: Use MyDB;Query database: SHOW DATABASES;Common operations on database tables:View table structure: DESC table nameCreating Table: Create table table name (column list type, column Name 2 column type 2, ...);To modify a table:Modify table name: ALTER table name RENAME to new show;Add Co

', 65000.00 );INSERT into Company(NAME,Age,ADDRESS,SALARY)VALUES( ' David ', 27, ' Texas ', 85000.00 );INSERT into Company(NAME,Age,ADDRESS,SALARY)VALUES( ' Kim ', 22, ' South-hall ' , 45000.00 INSERT into company (name,age ,address,salary) Span class= "PLN" > VALUES ( ' James ' , 24, ' Houston ' , 10000.00 This inserts 7 tuples into the company table, at which time the records for the company table are as follows: ID NAME Age ADDRESS SALARY---------- ---------- ---------- --------

nested queriesShow the city's non-Shanghai staff information:SELECT * from staff where warehouse number in (select warehouse number from warehouse where city! = ' Shanghai ')Displays the average sales amount and warehouse number information for employees in different warehouses, provided that the average sales amount is greater than 15000 or the maximum sales amount is less than 18000 and the average wage of all employees is greater than 800 of the warehouse area:Select warehouse Number, AVG (a

) --------------------------------------------------------------------------------------------------------------- -----------------------------Ask Answer Series:29. "51cto/bbs" help: How to accumulate data through the stored procedures for automatic storage ...30. The "QQ group" uses SQL Profiler for performance impact 31. How does "51cto/bbs" use SQL statements to save (fetch) files to the database? 36.

Tags: completion time desc name Ott des ESC composition cotIt is necessary to familiarize yourself with the four tables under this user.View all table names:SELECT * FROM tab;To view the structure of each table:DESC 表名称；1, Department table: DeptNo Name type description1 DEPTNO Number (2) department numbers, two digits.2 dname VARCHAR2 (14) department name, up to 14 characters3 LOC VARCHAR2 (13) Department location2. Employee table: EMPNo Name type description1 EMPNO numer (4) The employee's numb

the contents of the SQL buffer to check if your modifications are correct. Example 3-8 Sql> L Example 3-8 results Example 3-8 results table name The changes you made are accurate. So how do we run this statement?3.4 '/' (RUN) commandYou certainly do not need to reenter this statement because this statement is already in the SQL buffer. Oracle provides the Slq

Label:　　　 When I recently helped the customer with the issue of publishing subscriptions, I suddenly encountered an issue in which the following errors were reported in the publication subscription, and an error occurred while performing the ALTER TABLE operation: 　 　　　　 The question is weird. What is the relationship between a publish subscription and the CLR? What is MemToLeave memory? Recall learning architecture, I did see MemToLeave memory, but

();} Finally{jdbcutils.close (NULL, STAT, conn);}}}Then look at the second way:Import java.sql.connection;import java.sql.preparedstatement;import com.itheima.util.jdbcutils;/* CREATE table Psbatch (ID int primary key auto_increment, name varchar (30)); *//*prparedstatement implementation of batch processing: The advantages: There is a pre-compilation mechanism, high efficiency. When you execute multiple structures that have the same parameters, you do not need to repeat the skeleton of

Label:Original: Simple learning of locks in SQL ServerBrief introductionIn SQL Server, each query will find the shortest path to achieve its own goal. If the database accepts only one connection at a time, only one query is executed. Then the query is, of course, M.F.B. s to complete the work. For most databases, however, multiple queries need to be processed at

Recently learned SQL in Teradata environment. Here to record the study of the knowledge points, as a record.Directory: About SQL learning and the online database used Table Union (join) SQL Sub-query Create a new field at select (as, Case time) Data Grouping (group BY + aggregate function count

e.mgrid=m.empid )- SELECT * from Emplist Define a variable, accept the employee ID that you want to query, set to 2, that is, query all the subordinate information below the employee number 2nd. The use of CTE there are many, here is only a few basic usage, if there are ideas, can be proposed, hope to learn together! SQL Server Learning Note 1:http://www.cnblogs.com/liupeng61624/p/4354983.html

Deep Learning of SQL Server aggregate function algorithm optimization skills, SQL server Aggregate functions are widely used in practical work to cope with various needs. Optimization of Aggregate functions naturally becomes a key point, whether a program is optimized or not directly determines the statement cycle of the program.

Http://www.cnblogs.com/lovecherry/archive/2007/08/13/853754.htmlNow LINQ to SQL data is not a lot, I have limited level, if wrong or misleading please point out, thank you. Step-by-Step Study of LINQ to SQL (i): Preliminary knowledge Step-by-Step Learning LINQ to SQL (ii): DataContext and Entities Step-

Spring + SpringMVC + MyBatis deep learning and setup (5) -- dynamic SQL and springmvcmybatis Reprinted please indicate the source: http://www.cnblogs.com/Joanna-Yan/p/6908763.html I have talked about Spring + SpringMVC + MyBatis deep learning and building (4) -- MyBatis input ing and output ing Mybatis core: flexibly operate