sql char values

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

Comparison of data typesChar represents a fixed length, and the longest n-word varchar represents the actual length of the data type, such as: if it is a char type, when you enter a character that is less than the length, then a space is added, but

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 Introduction to null valuesNULL is a unique data type in the database. If a column in a record is NULL, the value of this column is unknown and uncertain. Since it is unknown, there are several possibilities. Therefore, NULL is not a definite

Normal spacesBefore and after spaces, use LTrim and RTrim, for example: LTrim (RTrim (Name))Middle space, replace with replace function, for example: replace (Name, ' ', ')If it is an ordinary space, it is easy to replace, but sometimes encounter

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

Oracle defines string types VARCHAR2 and char specify the length of the usage as follows:VARCHAR2 ( ) is a number between 1~4000 that represents up to 4000 bytes of storage space.char ( ) is a number between 1~2000 that represents up to 2000 bytes

Differences between varchar and nvarchar: Varchar (n)Variable-length and non-Unicode character data with a length of n Bytes. N must be a value between 1 and 8,000. The storage size is the actual length of the input data bytes, rather than n Bytes

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

1. The length of char is fixed, the length of the VARCHAR2 can vary, for example, the storage string "abc", for Char (20), which means that the characters you store will occupy 20 bytes (including 17 null characters), in the database it is occupied