learn sql in 21 days

Label:Using SQL statements for exact queries in Excel (2012-08-21 00:00:00)reproduced Tags: Zheng Laiyi data analysis Excel SQL data query matching Category: 07.MSoffice Today on Weibo to see the @ data Analysis Select share an article on the "Use of SQL statements in Excel to achieve

Tags: SQL base time zone function (21)Use a data type to store the time difference between two datetime valuesUse the following date-time functions:–current_date–current_timestamp–localtimestamp–dbtimezone–sessiontimezone–extract–tz_offset–from_tz–to_timestamp–to_yminterval–to_dsintervalTime_zone can be set to:Absolute offsetTime zone of the databaseOS local time zoneZone Domain nameAlter session Set Time_z

SQL Study Notes (21) ---------- add Foreign keys and Study Notes ---------- I have been busy with exams recently! As soon as I saw the exam, I was covered! Completely blank brain, uncontrolled, coupled with abnormal invigilators, let alone how painful it is. Fortunately, after successfully completing the test, I took some time out to learn about MySQL and Oracle

The SQL statement is used to calculate the number of working days between two dates. /*Due to a strange demand at work, the SQL language is used to calculate the number of working days between two days.It is set to have 5 working days in a week, from Monday to Friday.Note:Nu

SQL Date Subtraction DateDiff () returning two date days Definitions and usageThe DATEDIFF () function returns the number of days between two dates. GrammarThe DATEDIFF (date1,date2) date1 and Date2 parameters are valid date or date/time expressions. Note: Only the date part of the value participates in the calculation. DATEDIFF (EXPR1,EXPR2): Returns EXPR1-E

server| function In fact, this function is not provided by SQL Server, is tofu written, we do not because of tofu piece of everyone To use a stone to hit tofu: In fact, since this function generated after we use, it is impossible to distinguish between this Whether the function is SQL Server or a custom function, this is one of the new features that SQL2K brings to us Let's take a look at the meaning of thi

dlinq is adjusted accordingly, and the name is "LINQ to SQL. There are still traces of this evolution in my blog. However, the author has not come and updated its content. VS was also changed from the original version 2007 to vs2008. Now beta2is released. The rise of a language and a technology requires a large number of people to use it, recognize its advantages, and promote it. I assume that all readers have C #1.1 language basics. In addition, thi

Label:The first two days of the lesson summary of the following, generally in the connection layer basically call those classes. Generally includes three classes of System.Data.SqlClient and System.Data under Sqlconnection,sqlcommand,sqldatareader. If you want to read from the configuration file, you also need to system.configuration. In the end how to connect I think there are books, I will not write. Write a single Sihuo, and the teacher in the clas

Oracle Learn the use of Oracle SQL Loader One: Features of SQL loader Oracle has a number of tools that can be used to migrate, backup, and restore data. But each tool has its own characteristics. For example, exp and IMP can export and export data in the database, which is a good tool for database backup and recovery, so it is mainly used in the hot backup and

I. Introduction SQL statements, such as DOS and Unix commands, are countless. I plan to learn and review SQL statements in this article. Ii. SQL language verb Query select Define create, drop, alter Insert, update, and delete operations Control Grant and revoke Iii. SQL da

All together to learn Nhibernate+nunit (Vs2012+sql Server2008)Category: C#2013-08-10 18:47 1589 people read reviews (5) Favorite reportsNhibernatenunitvisual Studio 2012If you have not heard of NHibernate or NUnit, then, congratulations, like me, shake hands. If you are already an old soy sauce, that dear different do not take you to play, please consciously detour,,,. I would like to dedicate this article

types,Note: The data types supported by different database management systems vary, as in SQL Server, the number data type is written as decimal or nurneric. 2.3. Date data typeDate uses 10 characters to hold a 4-digit year, a two-digit month, and a day value of two-digit days, in the format: 2014-01-01.Time value, which refers to the values of timing, minutes, and seconds. Seconds do not contain decimals