sql char code

Charvarcharvarchar2 differences: 1. the length of CHAR is fixed, while the length of VARCHAR2 can be changed. For example, the storage string "abc", for CHAR (20 ), it indicates that the characters you store will occupy 20 bytes (including 17 null

Char varchar varchar2 the difference http://blog.csdn.net/honglei_zh/article/details/7172538Difference:1. The length of the char is fixed, and the length of the VARCHAR2 is changeable, for example, storing the string "abc", for Char (20), which

1. charFixed length, n characters at most.2. varcharA variable string with a maximum length of n.(N is an integer. The maximum length of n varies with different databases)If we set the length to 10: char (10) and varchar (10), then we set the value

13. T-SQL and SQL query AnalyzerWhat is SQL?What is T-SQL?Introduce new features of T-SQLHow to Use T-SQLSummaryIn this chapter, we will introduce some basic concepts about the Structured Query Language and transact-SQL and their differences. This

The SQL injection vulnerability attacks have aroused widespread concern because they can penetrate the firewall and Intrusion Detection System to damage your data layer. Whether it is the first or second-level injection attack, if you look at 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

Use the SQL Server northwind database's MERs table 1) Code I 1 Declare   @ Ccoustomerid   Char ( 5 ) 2 Select   @ Nccoustomerid   =   Null ; 3 Select   *   4 From MERs 5 Where Customerid

I. Evolution: The varchar type of MySQL database has a maximum length limit of 255 in the version below 5.0.3, and its data range can be 0~255. In the MySQL5.0.3 and above versions, the length of the varchar data type is supported to 65535, which

The maximum length of the MySQL database varchar type in versions earlier than 5.0.3 is 255, and its data range can be 0 ~ 255 The maximum length of the MySQL database varchar type in versions earlier than 5.0.3 is 255, and its data range can be 0 ~

A marketplace has been injected to obtain more than 500 million user information and more than 600 million merchant information. User Data is leaked, and the mobile phone number of the ID card is exposed.   GET