Syntax error MySql trigger: While_Sym - mysql

Question

I'am developing a small project with PHP and MySql on a Wamp server. I just discovered the wonderful principle of SQL triggers. Hum... well. It would be wonderful if I could use it.
Indeed I have a problem with the following script:
BEGIN
SET #liste = NEW.reponse
WHILE LEN(#liste) > 0
BEGIN
IF PATINDEX('%,%',#liste) > 0
BEGIN
SET #choix = SUBSTRING(#liste, 0, PATINDEX('%,%', &liste))
INSERT INTO resultat (referendum, choix) VALUES (NEW.id, #choix)
SET #liste = SUBSTRING(#liste, LEN(#choix + ',') + 1, LEN(#liste))
END
END
END
I would like to execute this trigger after the insertion of a record in table "Referendum". In this table, there is a field "reponse" which contains the different possible answers. This field contains this kind of data: "Yes,No,I don't know". For each new question, I want to insert a new record in table "Resultat" per possible answer.
In my example, three new records: one for Yes, one for No and one for I don't know.
My code comes from an example on the internet but it doesn't work properly. SQL returns a syntax error with message "While_Sym expected"...
I tried to add semicolon following what I found on the internet but no way...

Answer 1

I guess you need something like this:
CREATE TRIGGER mytrigger AFTER INSERT
ON Referendum FOR EACH ROW
BEGIN
DECLARE cnt int;
DECLARE str varchar(100);
Set cnt = CHAR_LENGTH(NEW.reponse)
- CHAR_LENGTH(Replace(NEW.reponse,',','')) +1;
WHILE cnt > 0 DO
Set str = SUBSTRING_INDEX(
SUBSTRING_INDEX( New.reponse,',', -cnt)
,',',1);
INSERT INTO resultat (referendum, choix)
VALUES (NEW.id, str);
Set cnt = cnt - 1;
END WHILE;
END;
Demo: http://sqlfiddle.com/#!2/c7321/1
Some thoughts:
There are no PATINDEX nor LEN functions in MySql, they come from SQL Server.
Most functions are not standard in SQL, one shouldn't expect that something that works on database X should also work on database Y (and vice versa)
You always need to check the manual.
There is difference in MySql between #variable and variable - they are not the same (opposite to SQL Server where there is only one kind of variables --> #variable).
Please refer to documentation to learn about #user_definied_variables and local_variables
http://dev.mysql.com/doc/refman/5.7/en/user-variables.html
http://dev.mysql.com/doc/refman/5.7/en/declare-local-variable.html
Depending on your client software you may need to use also DELIMITER xx command, for example in mysql console client or MySql-Workbench you need something like this to create a trigger without syntax errors:
DELIMITER $$
CREATE TRIGGER mytrigger AFTER INSERT
ON Referend ......
......
......
END;
$$
DELIMITER ;