ASCII, Ord function usage in MySQL

One, ASCII (STR1)

Returns the ASCII code value of the leftmost character of the string str. If Str is an empty string, returns 0. If STR is NULL, return null

Example:
1.

The code is as follows	Copy Code
Mysql> Select ASCII (' Hi '); + ————-+ | ASCII (' Hi ') | + ————-+ | 104 | + ————-+ 1 row in Set

104 is the ASCII value of H

2. ASCII values for output B and B

The code is as follows	Copy Code
Mysql> SELECT ASCII (' B ') as Lower_case, ASCII (' B ') as upper_case; + ———— + ———— + | Lower_case | Upper_case | + ———— + ———— + |         98 | 66 | + ———— + ———— + 1 row in Set

3. Using the ASCII function in the WHERE statement

Output Aut_name The ASCII value of the first letter is less than 70 data

The code is as follows	Copy Code
SELECT Aut_name,ascii (Aut_name) as "ASCII value of 1st character" From author WHERE ASCII (aut_name) <70;

4. There is no data in the output field that does not have an ASCII value

The code is as follows	Copy Code
SELECT * FROM table_name WHERE not Column_to_check REGEXP ' [a-za-z0-9.,-] ';

5. Use a computed string with substring the second subsequent ASCII value

The code is as follows	Copy Code
Mysql> Select ASCII (SUBSTRING (' database ', 2, 1)); + ———————————-+ | ASCII (SUBSTRING (' database ', 2, 1)) | + ———————————-+ | 97 | + ———————————-+ 1 row in Set

Second, Ord function

ORD (str)

If the string str leftmost character is a multibyte character, it is passed in a format

The code is as follows	Copy Code
((*256+ (second byte ASCII code)) [*256+third byte ASCII code ...]

Returns the ASCII code value of the character to return the multibyte character code. If the leftmost character is not a multibyte character. Returns the same value returned with the ASCII () function.

code is as follows	copy code
1 MySQL > select ORD (' 2 '); 2            ->