sql server varchar max performance

= 'where ('+ @ condition +') '-- this condition is added if no conditions exist.EndSet @ SQL = 'select @ intresult = count (*) from' + @ TB + @ where2Exec sp_executesql @ SQL, n' @ intresult int output', @ intresult output -- calculate the total number of recordsSelect @ pages = ceiling (@ intresult + 0.0)/@ pagesize) -- calculate the total number of pagesIf @ orderby = 0Set @

CONVERT (varchar), GETDATE (), 121): 2006-05-16 10:57:49.700 Select CONVERT (varchar), GETDATE (), 126): 2006-05-16t10:57:49.827 Select CONVERT (varchar), GETDATE (), ():?????????? 1427 10:57:49:907am In SQL database, there is a class of functions that have to be mentioned, that is,

write cache exists and the algorithm is normal, RAID5 is even better than raid10, although there may not be much difference (here we should assume that there is a certain size of storage, enough write cache, and there is no bottleneck in the CPU for computing and verification ). This is because the raid check is completed in the cache. For example, for RAID 5 of four disks, you can calculate the check in the memory and write three data and one verification at the same time. Raid10 can only wr

Mysql:Char defines stored characters, the actual storage is also stored as characters, size char (255 characters), note is not byte.What is the difference between a character and a byte?A byte is a unit of information stored in a computer, a byte is eight bits, a character is a, B, C, and some symbols, usually in a computer with a byte, that is, generally accounted for a byte, but there is not generally, according to the specific encoding each character occupies a different number of bytes, as i

SQL Server performance optimization skills, SQL Server Performance Optimization 1. Select the most efficient table name sequence (only valid in the rule-based Optimizer) The SQL

SQL Server address search performance optimization and SQL server performance optimization This is an example of a long time ago. Now, I have no intention of discovering the materials, so I will take it out and try again. 1. Requi

In a recent interview, the interviewer asked the difference between varchar and nvarchar, remembering the difference between fixed length and variable lengths, but failed to speak. Later, on the Internet to find the next user summary of the difference. Make a memo here:One, the difference between Char,varchar,nchar,nvarchar in SQL

that the length of the corresponding length, and the variable length character data will not be filled with spaces, the exception is that the text storage is also variable length. (6) How do I use these types? If you are sure of the length of the stored data and do not pack in Chinese, you can choose the char type. If you are sure of the stored data length, but may include Chinese, you can choose the nchar type. If you are unsure of the length of the

the efficiency of a varchar high. (4) Why use nvarchar? with n prefixes, n denotes Unicode characters, that is, all characters account for two bytes, Nchar,nvarchar Character, the English characters only need one byte storage is sufficient, but the Chinese character is numerous, requires two bytes of storage, English and Chinese characters are prone to confusion, the Unicode character set is to solve the problem of incompatible character sets, all of

In SQL Server, smaller data can be stored using varchar (n), nvarchar (n), and varbinary (n) types, storing large data, using varchar (max), nvarchar (max), and varbinary (max ) Instead

Tags: advance option ons base own data mem conf everDo SQL Server memory Max memory set the idea, the maximum value of 0, how can not connect to the database, which is really urgent ah, finally saw a text command to save back, other very simple urgency is not come up.1. Pause all SQL

a varchar high.(4) Why use nvarchar?with n prefixes, n denotes Unicode characters, that is, all characters account for two bytes, Nchar,nvarcharCharacter, the English characters only need one byte storage is sufficient, but the Chinese character is numerous, requires two bytes of storage, English and Chinese characters are prone to confusion, the Unicode character set is to solve the problem of incompatible character sets, all of its characters are r

In the development of database application project, some binary image data are often used, and the data of storing and reading the display image mainly adopts path link method and memory flow method. The path link method is to save the image file in a fixed path, the database only stores the path and name of the image file, this method has small database capacity, fast access speed, but less security; the memory flow method is to store the binary data directly in the database, this method is con

Tags: fixed har char trim definition length take number requires VarThe length of the char type is immutable in SQL Server, and the length of the varchar is variable.When depositing data:If the data type is char, when a fixed length of a field is defined, if the length of the stored data is less than the length of char, then the length of data stored in the data

With regard to the use of SQL Server Profiler, there are already many tutorials on the web, such as this article: SQL Server Profiler: How to use and metrics. Microsoft Official Documentation: https://msdn.microsoft.com/zh-cn/library/ms179428 (v=sql.105). aspx is described i

Tags: decimal point index VAR technology does not convert SRC int typeSELECT * FROM table nameOrder BY Convert (int,left (column name, CHARINDEX ('. ', column name + '. ') -1) ASC, column name ASCCHARINDEX ('. ', column name) query first. (dot) in the number ofCHARINDEX ('. ', column name + '. ') Give no data to the last side Add. (points) This allows the first digit to be found without a decimal point.Left (column name, CHARINDEX ('. ', column name)) Query decimal valueLeft (column name, CHARIN

Char stores a fixed-length string with a maximum length of 8,000 bytes.varchar stores a variable-length string with a maximum length of 8,000 bytes.NCHAR stores a fixed-length Unicode string with a maximum length of 4,000 characters.Nvarchar stores a variable-sung Unicode string with a maximum length of 4000 value characters.Note that the following are:The allocation of storage space will be different, such as varchar (10) allocated 10 bytes nvarchar

value is 0, which means that the maximum number of connections for SQL Server is 32767 by default.Get the maximum number of connections currently set:Select value from Master.dbo.sysconfigures where [config]=103How to monitor the number of SQL Server connections/* Query the number of connections */Select Loginame,coun

Using SQL Server Management StudioTo configure the user connections option1.In Object Explorer, right-click a server and click Properties.2.Click the Connections node.3.Under Connections, in the Max number of concurrent Connections box, type or select a value from 0 through 32767 to set t He maximum number of users tha

following is the optimization of the SQL statement in fact, SQL is not complex, but the data of these tables are slightly larger, but also nested inside more complex business logic, history after several rounds of "master" in the index of the whole side of the optimization, can also run normally but over time, the amount of data in the table is getting larger , boiled frog in warm water,