ansi sql standard

used to store a large number of non-uniform encoded character data. This data type can have a maximum of 231-1 or 2 billion characters Nchar Unified encoded character type (Unicode) The Nchar data type is used to store fixed-length, uniformly encoded character data. Uniform encoding uses a double-byte structure to store each character, rather than a single-byte (normal text case). It allows for a large number of extended characters. This data type can store 4000 charact

method suitable for ourselves based on the actual situation. I will introduce you to a standard SQL statement to obtain qualified data. For example, from 10th to 20 records that meet the conditions (in the where Statement. In this way, there is a necessary condition for getting a record. There must be a field that can identify the record order, such as ID and time. The following is an example:Query 10th to

In most applications, it is common to return a large number of qualified records. The most typical method is to search. In the search application, the user gives the search criteria and the server finds the matching records. However, a search usually returns a large amount of data records. If you are on a webpage, the page is usually implemented by pagination. The page provides buttons such as the previous page and next page to implement paging.The following methods are used to implement paging:

] [Cluster] Index Index name> onTable name>(Column Name 1>[][,]...);CreateClusterIndexInd_name onStudent (Sname);The default is ascending ASC, and in addition, descending is desc2. DeleteDrop Index index name >;Section Three data queryFirst, formatSelect [all|distinct] Target column Expression>[,]... from Table name or view name>[,]...[where][Group by]][Order by]]1. Target column expression */table name. */count (*)/Field name expression2. Conditional expressionsSecond, single-table query1. Sel

A data query is the core operation of a database. SQL provides a SELECT statement for data query, which is flexible to use and rich in functionality.Its general format isSelect [All | distinct]Target expression>[,]... .. fromTable name or view name>[,] |(SELECT statement) ( as)Alias>[where][GROUP by ]][OrderBy ]]; PS: The meaning of the entire SELECT statement above is that, based on the conditional expression of the WHERE clause, find the tu

SELECT clause to form the result table, based on the conditional expression of the WHERE clause.With a GROUP BY clause, the result is grouped by the value of column name 1, which is a group of tuples of equal value for the property columnoder by clause sort By Column Name 2 transaction value in ascending or descending orderSingle-Table QuerySpecify column Select All columns select * FROM tablename;Select several tuples in a tableEliminate duplicate values for rows select DISTINCT column name, .

']/value '). Value (' (value) [1] ', ' NVARCHAR (100) ')--get sql_textset @sql_text = @xmlData. Query ('//action[@name = ' Sql_text ']/ Value '). Value (' (value) [1] ', ' NVARCHAR (MAX) ')--start inserting data insert #MyData (database_id, Sql_text, username, client_hostname , Client_app_name, Cpu_time) VALUES (@database_id,--Database_id-int @sql_text,--Sql_text-nvarchar (max) @use Rname, @client_hostname, @client_app_name, @cpu_time) end TRY BEGIN catch END catch FETCH NEXT from Mycur into @

@ @fetch_statusDECLARE @id intSet @id = 1DECLARE Cur1 CURSOR forSELECT EmployeeIDFrom #tableOPEN Cur1;FETCH NEXT from Cur1;While @ @FETCH_STATUS = 0 and @id = 0BEGINFETCH NEXT from Cur1;END;CLOSE Cur1;Deallocate Cur1;GOThere is a problem with the bold sentence in the above example, when the value of the first value @id in the cursor does not meet the criteria, the @ @fetch_status value will not be 0.Note:return value 0 FETCH statement succeeded. The -1 FETCH statement failed or the row is n

different result.REPEATABLE READ (Repeatable Read)REPEATABLE READ (Repeatable Read) solves the problem of dirty reads. This level guarantees that the result of reading the same record multiple times in the same transaction is consistent. However, in theory, it is not possible to read the isolation level repeatedly to resolve another phantom read (Phantomread) problem. The so-called Phantom reads, when a transaction reads a range of records, another transaction inserts a new record within that r

Label:SQL Server 2008 is divided into SQL Server 2008 Enterprise Edition, Standard Edition, Workgroup Edition, Web Edition, Developer Edition, Express Edition, Compact 3.5 Edition, and its functions and functions vary, with SQL Server 2008 Express Edition is a free version. SQL Server 2008 Enterprise Edition

number of columns is unlimited. Where the number of columns in a mutable index is slower, the immutable index does not affect the write speed (ref.: https://github.com/forcedotcom/phoenix/wiki/Secondary-Indexing#mutable-indexing). 4: To Top-n query speed far beyond hive (reference: HTTPS://GITHUB.COM/FORCEDOTCOM/PHOENIX/WIKI/PERFORMANCE#TOP-N)5: Provides the characteristics of the rowkey, can achieve uniform distribution of data in each region (reference: https://github.com/forcedotcom/phoenix/

Today development colleague to me, said why Reporting Services server Report Management subscription options There is only the "New subscription" option, there is no "data-driven Subscription" option, to be honest, I also basically did not use this feature, so go to the official document to view about "data-driven subscription" of some knowledge.For a long while, the original SQL Server 2008 only evaluation, Developer, enterprise three versions suppor

Tags: core relationship arc tuple an independent display language controlChapter III relational database standard language SQL SQL Set data query, data manipulation, data definition and data control functions in one, the main features include: Integrated (unified language style for each part of the process) High degree of non-process Collection-oriented operation

Tags: io ar sp strong div on Art BS ADEnterprise DVD SQL Server 2005 Enterprise Edition (support for very large enterprises)32-bit DVD:ed2k://|file|cs_sql_2005_ent_x86_dvd.iso|972310528|4ceef4b959894fd78c8f8416b4ba533e|/64-bit DVD:ed2k://|file|cs_sql_2005_ent_x64_dvd.iso|1019222016|10fd11133a3e70dad665bedc1090ad28|/Standard Edition CD SQL Server 2005 Edition (for

Tags: io ar strong SP div Art C on REnterprise DVD SQL Server 2005 Enterprise Edition (support for very large enterprises)32-bit DVD:ed2k://|file|cs_sql_2005_ent_x86_dvd.iso|972310528|4ceef4b959894fd78c8f8416b4ba533e|/64-bit DVD:ed2k://|file|cs_sql_2005_ent_x64_dvd.iso|1019222016|10fd11133a3e70dad665bedc1090ad28|/Standard Edition CD SQL Server 2005 Edition (for s

if object_id('tempdb: #tempTable') is not NULL Begin Drop Table#tempTableEndSELECT TOP + [Campus],[academic year],[Exam Grade],[Exam Category],avg(language contains challenges)'Average score',STDEV(language contains challenges)'Standard deviation' into#tempTable from [Schoolanalyze].[dbo].[Score Analysis]Group by [Campus],[academic year],[Exam Grade],[Exam Category]Update [Schoolanalyze].[dbo].[Score Analysis]Set [

where Len (password) >12) error length is 12and 1= (SELECT COUNT (*) from admin where Len (password) =12) correct6. Guessing charactersand 1= (SELECT COUNT (*) from the admin where left (name,1) =a)---Guess the first bit of the user accountand 1= (SELECT COUNT (*) from the admin where left (name,2) =ab)---Guess the second digit of the user accountJust add one character at a time so guess, guess enough you just guessed how many bits of the right, the account even came outand 1= (select top 1 cou

= @xmlData. Query ('//acti on[@name = "username"]/value '). Value (' (value) [1] ', ' NVARCHAR (100) ')--get hostname SET @client_hostname = @xmlDat A.query ('//action[@name = "Client_hostname"]/value '). Value (' (value) [1] ', ' NVARCHAR (100) ')--Get Sql_textset @sql_text = @xmlData. Query ('//action[@name = ' sql_text ']/value '). Value (' (value) [1] ', ' NVARCHAR (MAX) ')--begins inserting the data insert #MyData ( database_id, Sql_text, username, client_hostname, CPU) VALUES (@database_i

('//action[@name = ' client_app_name ']/value '). Value (' (value) [1] ',' NVARCHAR (100) ')--Get Sql_textSET @sql_text = @xmlData. Query ('//action[@name = ' sql_text ']/value '). Value (' (value) [1] ',' NVARCHAR (MAX) ')--Start inserting dataINSERT #MyData(database_id,Sql_text,UsernameClient_hostname,Client_app_name,Cpu_time)VALUES (@database_id,--Database_id-int@sql_text,--Sql_text-nvarchar (max)@username,@client_hostname,@client_app_name,@cpu_time)END TRYBEGIN CATCHEND CATCHFETCH NEXT from

Cursors: is used to loop the table from top to bottom, and to concatenate values into strings.Example:The Dbo.titles table for the pubs database.1. Obtain the total price in the table: select sum from Dbo.titles2. But I want to get a result: Title, price.Proficient in asp,39 yuan; learning vc++,28; Java programming, 23 USDThe cursor is used:To declare a cursor:DECLARE Titprice CURSOR Fast_forward forSelect title, Price from Dbo.titles where priceTo open a cursor:Open TitpriceRecycled Mass Collec