Summary: common character processing functions in MYSQL databases

Source: Internet
Author: User
ASCII (str) returns the ASCII code value of the leftmost character of the str string. If str is a null string, 0 is returned. If 'str' is NULL, return NULL. MysqlselectASCII ('2');-50 mysqlselectASCII (2);-50 mysqlselectASCII ('dx ');-100 also

ASCII (str)
Returns the ASCII code value of the leftmost character of the str string. If str is a null string, 0 is returned. If 'str' is NULL, return NULL.
Mysql> select ASCII ('2 ');
-> 50
Mysql> select ASCII (2 );
-> 50
Mysql> select ASCII ('dx ');
-> 100
For more information, see the ORD () function.

ORD (str)
If the leftmost character of a string 'str' is a multi-byte character, the following code uses a pattern (first byte ASCII code) * 256 (second byte ASCII code )) [* 256 third byte ASCII code...] returns the ASCII code value of a character to return the multi-byte code. Assume that the leftmost character is not a multi-byte character. Returns the same value as that returned by the ASCII () function.
Mysql> select ORD ('2 ');
-> 50
 
CONV (N, from_base, to_base)
Convert numbers between different digit bases. Returns the string number of number N, which is converted from from_base base to to_base base. if any parameter is NULL, NULL is returned. Parameter N is an integer, but can be specified as an integer or a string. The minimum base is 2 and the maximum base is 36. If to_base is a negative number, N is considered as a signed number. otherwise, N is considered as an unsigned number. CONV works with 64-bit precision.
Mysql> select CONV ('A', 16, 2 );
-> '123'
Mysql> select CONV ('6e', 18, 8 );
-> '123'
Mysql> select CONV (-17,10,-18 );
-> '-H'
Mysql> select CONV (10 '10' '10' 0xa, 10, 10 );
-> '40'
 
BIN (N)
Returns a string of the binary value N. Here N is a long integer (BIGINT) number, which is equivalent to CONV (N, 10, 2 ). If N is NULL, return NULL.
Mysql> select BIN (12 );
-> '123'

OCT (N)
Returns the expression of a string with an octal value N. Here N is a long integer, which is equivalent to CONV (N, 10, 8 ). If N is NULL, return NULL.
Mysql> select OCT (12 );
-> '14'
 
HEX (N)
Returns the representation of a hexadecimal value N string. Here N is a long integer (BIGINT) number, which is equivalent to CONV (N, 10, 16 ). If N is NULL, return NULL.
Mysql & gt; select HEX (255 );
-> 'Ff'
 
CHAR (N ,...)
CHAR () describes parameters as integers and returns a string consisting of ASCII code characters of these integers. The NULL value is skipped.
Mysql> select CHAR (77,121, 81, '76 ');
-> 'Mysql'
Mysql> select CHAR (77, 77.3, '77. 3 ');
-> 'Mmm'
 
CONCAT (str1, str2 ,...)
Returns a string from the parameter link. If any parameter is NULL, NULL is returned. There can be more than two parameters. A numeric parameter is transformed into an equivalent string.

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.