ASCII
Description
Returns the ASCII code value of the first character in a string. This function only processes the first character of the string, returning only the ASCII value of the first character for multi-character strings.
Syntax
ASCII(<str>)
Parameters
| Parameter | Description |
|---|---|
<str> | The string to get the ASCII code of the first character. Type: VARCHAR |
Return Value
Returns INT type, representing the ASCII code value of the first character in the string.
Special cases:
- If the parameter is NULL, returns NULL
- If the string is empty, returns 0
- If the first character is not an ASCII character (code value greater than 127), returns the corresponding byte value
- For multi-byte UTF-8 characters, returns the value of the first byte
Examples
- Basic numeric characters
SELECT ASCII('1'), ASCII('234');
+------------+--------------+
| ASCII('1') | ASCII('234') |
+------------+--------------+
| 49 | 50 |
+------------+--------------+
- Letter characters
SELECT ASCII('A'), ASCII('a'), ASCII('Z');
+------------+------------+------------+
| ASCII('A') | ASCII('a') | ASCII('Z') |
+------------+------------+------------+
| 65 | 97 | 90 |
+------------+------------+------------+
- Empty string handling
SELECT ASCII('');
+-----------+
| ASCII('') |
+-----------+
| 0 |
+-----------+
- NULL value handling
SELECT ASCII(NULL);
+-------------+
| ASCII(NULL) |
+-------------+
| NULL |
+-------------+
- Special symbols
SELECT ASCII(' '), ASCII('!'), ASCII('@');
+------------+------------+------------+
| ASCII(' ') | ASCII('!') | ASCII('@') |
+------------+------------+------------+
| 32 | 33 | 64 |
+------------+------------+------------+
- Control characters
SELECT ASCII('\t'), ASCII('\n'), ASCII('\r');
+-------------+-------------+-------------+
| ASCII('\t') | ASCII('\n') | ASCII('\r') |
+-------------+-------------+-------------+
| 9 | 10 | 13 |
+-------------+-------------+-------------+
- Multi-character strings (returns only the first character)
SELECT ASCII('Hello'), ASCII('World123');
+----------------+------------------+
| ASCII('Hello') | ASCII('World123') |
+----------------+------------------+
| 72 | 87 |
+----------------+------------------+
- UTF-8 multi-byte characters
SELECT ASCII('ṭṛì'), ASCII('ḍḍumai');
+---------------+------------------+
| ASCII('ṭṛì') | ASCII('ḍḍumai') |
+---------------+------------------+
| 225 | 225 |
+---------------+------------------+
- Mixed numbers and characters
SELECT ASCII('9abc'), ASCII('0xyz');
+---------------+---------------+
| ASCII('9abc') | ASCII('0xyz') |
+---------------+---------------+
| 57 | 48 |
+---------------+---------------+
