Categories:

String & Binary Functions (General)

ASCII

Returns the ASCII code for the first character of a string. If the string is empty, a value of 0 is returned.

See also:

Syntax

ASCII( <input> )

Arguments

input

The string for which the ASCII code for the first character in the string is returned.

Returns

The value is an integer that is the numeric representation of the ASCII character. For example, if the input is the letter ‘a’, then the return value is 97.

Usage Notes

The value 0 is returned for either of the following cases:

  • The first character of the string contains the ASCII character corresponding to 0.

  • The string is empty.

To distinguish between these two cases, use the LENGTH function to determine whether the string is empty.

Examples

This example demonstrates the behavior for single ASCII characters, as well as special cases, such as multi-character strings, empty strings, and NULL values:

SELECT column1, ASCII(column1)
  FROM (values('!'), ('A'), ('a'), ('bcd'), (''), (null));
+---------+----------------+
| COLUMN1 | ASCII(COLUMN1) |
|---------+----------------|
| !       |             33 |
| A       |             65 |
| a       |             97 |
| bcd     |             98 |
|         |              0 |
| NULL    |           NULL |
+---------+----------------+