MySQL - ASCII() Function

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ASCII, which stands for American Standard Code for Information Interchange, is a character encoding standard used to represent text in computing and communication. There are 128 standard ASCII codes, each of which can be represented by a 7-digit binary number ranging from 0000000 to 1111111. Extended ASCII, on the other hand, adds an additional 128 characters, but these characters can vary between different computers, programs, and fonts.

The MySQL ASCII() function accepts a string value as a parameter and returns the ASCII (numeric) value of the leftmost character of the given string. If the string passed to the function is empty, it returns 0. If a NULL value is passed, the function returns NULL.

Syntax

Following is the syntax of MySQL ASCII() function −

ASCII(str)

Parameters

This function takes a string value as a parameter.

Return Value

This function returns the ASCII value (numeric code) of the given string.

Example

Following is an example of the MySQL ASCII() function. Here, we have passed the character 't' as a parameter to this function −

SELECT ASCII('t');

We can see in the output below that the ASCII value of 't' is '116' −

ASCII('t')
116

Example

Even when you pass the complete string 'test' as the parameter, the function still returns 116, which is the ASCII value of the leftmost character 't' −

SELECT ASCII('test');

Output of the above code is as shown below −

ASCII('test')
116

Example

Here, we passed the numeric value 9 as the parameter −

SELECT ASCII(9);

The output obtained is as follows −

ASCII(9)
57

Example

If an empty string is passed as a parameter, the function returns 0 −

SELECT ASCII('');

The result produced is as follows −

ASCII('')
0

Example

If a NULL value is passed as the parameter to the ASCII() function, it returns NULL −

SELECT ASCII(NULL);

We get the output as follows −

ASCII(NULL)
NULL

Example

The ASCII() function returns different values for uppercase and lowercase characters.

Here, we are retrieving the ASCII value for the letter 'A' (upper-case) −

SELECT ASCII('A');

Following is the output of the above code −

ASCII('A')
65

Now, we are retrieving the ASCII value for the letter 'a' (lower-case) −

SELECT ASCII('a');

We can see in the output below that the ASCII value differs for the lowercase character −

ASCII('a')
97

Example

Additionally, you can also use the ASCII() function with a column name of a table as a parameter and get ASCII values for all the first characters of its entities.

Let us create a table named "STUDENTS_TABLE" and insert records into it using CREATE and INSERT statements as shown below −

CREATE TABLE STUDENTS_TABLE (
   name VARCHAR(15),
   marks INT,
   grade CHAR
);

Now, let us insert records into it using the INSERT statement −

INSERT INTO STUDENTS_TABLE VALUES 
('Raju', 80, 'A'),
('Rahman', 60, 'B'),
('Robert', 45, 'C');

The STUDENTS_TABLE obtained is as follows −

name	marks	grade
Raju	80	A
Rahman	60	B
Robert	45	C

Following query retrieves the ASCII values of the grades in the STUDENTS_TABLE, along with the other students details −

SELECT *, ASCII(grade) FROM STUDENTS_TABLE;

After executing the above code, we get the following output −

name	marks	grade	ASCII(grade)
Raju	80	A	65
Rahman	60	B	66
Robert	45	C	67