SQL Tutorial

SQL ASCII Function

If you want to find a numerical value of a character which is in range of 0 to 255 you can use SQL ASCII function. If you pass a NULL string to ASCII function it will return NULL. If the string is empty, the function will return 0. Any character which its range is out of 0 to 255, the ASCII function will return an error or ignored based on implementation of RDBMS. Here is the syntax of ASCII function:

ASCII(expression)

Here is an example of finding ASCII value of character a in both lower case and upper case:

SELECT ASCII('a') AS lower_case_a,
       ASCII('A') AS upper_case_a
And here the output of ASCII value of lower and upper case of character 'a' 
lower_case_a  upper_case_a
------------  ------------
          97            65
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