Summary: common character processing functions in MYSQL databases

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.