CONVERT (varchar (10), field name, conversion format)CONVERT (nvarchar), count_time,121Convert is a date conversion function, typically in the time type (Datetime,smalldatetime) and the string type (Nchar,nvarchar,char,varchar)The 3 parameters of
CONVERT (varchar (10), field name, conversion format)CONVERT (nvarchar), count_time,121Convert is a date conversion function, typically in the time type (Datetime,smalldatetime) and the string type (Nchar,nvarchar,char,varchar)The 3 parameters of
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
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
Use the following code at the beginning:
alter proc getSerialNO@TYPE VARCHAR(2),@serialNO VARCHAR(10) OUTPUTASif (upper(@type) ='TR')begin select @serialNO = SERIALNO from tb_trserialno set @serialNO = @serialNO + 1 update tb_trserialno set SERIALNO
MySQL Char,varchar,text,blob is a few links but there are a lot of different types of fields, which is the basis of MySQL, but the foundation did not learn, bad to fill.Let's summarize briefly:Char: fixed length , maximum 255 charactersVARCHAR:
Recent project adjustments mainly involve changes to the length of database fields. In DB2, the only way to modify the length of a char field seems to be to delete the table and recreate it. Therefore, the question of which varchar and Char are used
FromHttp://www.cnblogs.com/billyxp/p/3548540.htmlThe design of varchar (10000) has been discussed recently in the design of table structure, and we will analyze and analyze them.First, we first popularize common sense:1, char (n) and varchar (n) in
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