sql server varchar max performance

This article is from the 51cto blog (cannot stop V) Varchar uses a single byte to store data in SQL Server. nvarchar uses Unico to store data. when a Chinese character is stored in SQL Server, it is saved as two bytes (generally Unico encoding), and an English character is

Conversion: differences between char, varchar, text, nchar, nvarchar, and ntext in SQL Server Many developers often do not consider the char and varchar types when designing databases. Some developers do not pay attention to them because the storage price is getting cheaper and cheaper, I forgot some of the ba

its characters are expressed in two bytes, That is, the English character is also represented in two bytes. the length of the nchar and nvarchar is between 1 and 4000. Compared to char and varchar, nchar and nvarchar store up to 4,000 characters, whether in English or Chinese characters, while char and varchar can store up to 8,000 English and 4,000 Chinese characters. It can be seen that the use of nchar,

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 stored data, store only English, the best use of the number varchar If you are unsure of the length of the stored data, it is possible to have Chinese, you can choose the nvarchar type, a

For general string fields in the program, SQL Server has char, varchar, nchar, and nvarchar types. What are the differences between these four types? Here we will make a comparison. 1. Fixed Length or variable length The so-called fixed length is fixed length. when the length of the data to be saved is insufficient, an English space will be automatically filled b

For general string fields in the program, SQL Server has char, varchar, nchar, and nvarchar types. What are the differences between these four types? Here we will make a comparison. 1. Fixed Length or variable length The so-called fixed length is fixed length. when the length of the data to be saved is insufficient, an English space will be automatically filled b

For fields with generic string types in your program, there are four types of char, varchar, nchar, and nvarchar in SQL Server, so what's the difference between these four types? 1. Fixed-length or variable-length The so-called fixed-length is long, when the length of the data to be saved will automatically fill in the back of the English space, so that the len

In SQL, convert the varchar type to the int type and then sort it. If the database ID is set to the orderbyid OF THE varchar type during query In SQL, convert the varchar type to the int type and then sort it. If the database ID is set to the order by id of the

Data Types of fixed-length (char) and variable-length (varchar) characters Char [(n)] Character data with a fixed length of n Bytes and is not Unicode. N must be a value between 1 and 8,000. The storage size is n Bytes. The synonym for char in the SQL-92 is character. Varchar [(n)] Variable-length and non-UNICODE character data with a length of n By

Make a comprehensive comparison between the title char and varcharSource: [ogdev] Browse: [86]It is proved that Char has better performance than varchar when the character length is certain, while char fields have slightly worse performance when the length is not sure. This can be reflected under the sqlserver database, and this field is frequently used.Differenc

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

Label:SELECT CONVERT (varchar), CAST (@testFloat as Decimal (38,2)))SELECT STR (@testFloat, 38, 2) Import from Excel to sql2000, there is a column "contact" has become a float type, I want to convert to nvarchar type, with the following statement Select convert (nvarchar (+), convert (int, contact)) from employeeGo Data overflow, no! Select convert (nvarchar), CONVERT (Decimal (11,0), contact) from employeeGo Data Conversion Success! SELECT CONV

Tags: convert har arch database share picture data type serve error colorSee SQL, use DATEADD () to convert the Times title error, because the database table in the data format is incorrect, the data format is incorrect, the data format is incorrect, the important thing to say 3 times !Ca.batch_no the first 8 bits must be date format YYYYMMDD, otherwise it will error!When a title error occurs, first troubleshoot the

migrated row pointing to the new block for storing row data, this means that the row id of the migrated ROW will not change. "Block is the smallest data organization and management unit in oracle, the storage space unit of data file disks, and Minimum unit of database I/O ( That is to say, both read and write are the size of a block. If the block is not full, the varchar field with the length of the updated content is changed, and the

Tags: quotes HTTP O365 class SQ convert entry initial SQL ServerThe solution for converting float to varchar into a scientific counting method in MSSQLWhen the system was initialized, because of a colleague, there was no single quotation mark in front of the numeric data, resulting in a float type after entering the databaseWe need to make the following conversions to change the data to a

Tags: SQL ServerSQL Server can not be lost, review; varchar (n) Length n bytes of variable-length, non-Unicode character data. n must be a numeric value between 1 and 8,000. Storage size is the actual length of bytes of input data, not n bytes. nvarchar (n) contains a variable-length Unicode character data of n characters. The value of n must be between 1 and 4,

SELECT CONVERT (varchar), CAST (@testFloat as Decimal (38,2))SELECT STR (@testFloat, 38, 2) Importing from Excel to sql2000, there is a list of "contacts" that have become float types, and I want to convert to nvarchar type, using the following statement Select convert (nvarchar), convert (int, contact) from employeeGo Data overflow, no! Select convert (nvarchar), CONVERT (Decimal (11,0), contact) from employeeGo Data Conversion Successful! SELE

Tags: field issues database SQL statement Refresh SQL Novice Color BSPA field property in SQL Server is varchar, I want to change this field to int type? This is a little annoyed, as a novice to face these problems really a bit difficult, this is also I found on Baidu, as th

SQL server char nchar nvarchar varchar region, nchar Char stores a fixed-length string with a maximum length of 8000 bytes. Varchar stores variable-length strings with a maximum length of 8000 bytes. Nchar stores Unicode strings of a fixed length. The maximum length is 4000 characters. Nvarchar stores the Unicode s

Description and comparison of database storage types (nchar, char, nvarchar, varchar) for database SQL Server1.char Type:The English (ASCII) characters occupy 1 bytes, a Chinese character occupies 2 bytes, char is convenient to store the fixed length data, the index on the Char field is very efficient, such as the definition of char (10), then regardless of whether the data you stored is 10 bytes, it takes