MySQL 5.7 - ASCII Each Character in a String - mysql

Question

I'm looking to do some validation of data replication between some different database systems, with different character sets (potentially) and a third party software that migrates the data. To help test an aspect of this, I'm looking to do something like the following.
ASCII(foo) returns the value for the first character in the string. Is there a way to get the ascii values for all characters in a string in one go, in one select statement? Something like concating the values together, separated by a space. E.g. If the string was hello then the output would be 104 101 108 108 111
Reference:
select ascii('h'); -- 104
select ascii('e'); -- 101
select ascii('l'); -- 108
select ascii('o'); -- 111

Answer 1

Just had the same problem, so here is a procedure that does the work:
DELIMITER $$
CREATE PROCEDURE string_to_ascii(IN inputStr VARCHAR(255))
BEGIN
DECLARE strLen INT DEFAULT 0;
DECLARE idx INT DEFAULT 0;
DECLARE current_char VARCHAR(1);
DECLARE current_char_ascii VARCHAR(10);
DECLARE outputStr TEXT;
IF inputStr IS NULL THEN
SET inputStr = '';
END IF;
SET strLen = CHAR_LENGTH(inputStr);
SET idx = 1;
WHILE idx <= strLen DO
SET current_char = SUBSTR(inputStr, idx, 1);
SET current_char_ascii = ASCII(current_char);
IF idx = 1 THEN
SET outputStr = current_char_ascii;
ELSE
SET outputStr = CONCAT(outputStr, ",", current_char_ascii);
END IF;
SET idx = idx+1;
END WHILE;
SELECT outputStr;
END
$$
DELIMITER ;
Usage:
> CALL string_to_ascii('hello');
+---------------------+
| outputStr |
+---------------------+
| 104,101,108,108,111 |
+---------------------+
If you prefer to use it as a function:
DELIMITER //
CREATE FUNCTION string_to_ascii ( inputStr TEXT )
RETURNS TEXT
DETERMINISTIC
BEGIN
DECLARE strLen INT DEFAULT 0;
DECLARE idx INT DEFAULT 0;
DECLARE current_char VARCHAR(1);
DECLARE current_char_ascii VARCHAR(10);
DECLARE outputStr TEXT;
IF inputStr IS NULL THEN
SET inputStr = '';
END IF;
SET strLen = CHAR_LENGTH(inputStr);
SET idx = 1;
WHILE idx <= strLen DO
SET current_char = SUBSTR(inputStr, idx, 1);
SET current_char_ascii = ASCII(current_char);
IF idx = 1 THEN
SET outputStr = current_char_ascii;
ELSE
SET outputStr = CONCAT(outputStr, ",", current_char_ascii);
END IF;
SET idx = idx+1;
END WHILE;
RETURN outputStr;
END; //
DELIMITER ;
And then the usage will be:
> SELECT string_to_ascii('hello');
+--------------------------+
| string_to_ascii('hello') |
+--------------------------+
| 104,101,108,108,111 |
+--------------------------+