Cannot declare variable in MySQL trigger - mysql

Question

I am having difficulty creating the following trigger in MySQL:
CREATE TRIGGER TRG_COMPLETE_REMINDER
AFTER UPDATE ON reminders
FOR EACH ROW
BEGIN
DECLARE
new_date DATE;
IF (NEW.complete = 1 AND recurrence <> 'NONE') THEN
CASE recurrence
WHEN '1 WEEK' THEN
SELECT INTO new_date NEW.date + INTERVAL 7 DAY;
WHEN '1 MONTH' THEN
SELECT INTO new_date NEW.date + INTERVAL 1 MONTH;
WHEN '3 MONTH' THEN
SELECT INTO new_date NEW.date + INTERVAL 3 MONTH;
END CASE;
INSERT INTO reminders (description, date, userID, complete, recurrence)
VALUES (NEW.description, new_date, NEW.userID, 0, NEW.recurrence);
END IF;
END;
The issue seems to be occurring where I attempt to declare new_date. MySQL returns the following error message:
#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'INTO new_date NEW.date + INTERVAL 7 DAY' at line 8
I would like this trigger to create a new reminder record when the complete attribute changes to 1. The new record should have a date greater than the original record, depending on the value stored in recurrence.

Answer 1

Two corrections fixed the issue:
Correcting the order of clauses in the SELECT statement (i.e.
moving INTO new_date after SELECT new_date + INTERVAL 7 DAY)
Adding DELIMITER // before creating the trigger

Answer 2

Rather than use a variable you can use a CASE expression right in the INSERT statement:
CREATE TRIGGER TRG_COMPLETE_REMINDER
AFTER UPDATE ON reminders
FOR EACH ROW
BEGIN
IF (NEW.complete = 1 AND NEW.recurrence <> 'NONE') THEN
INSERT INTO reminders
(description,
date,
userID, complete, recurrence)
VALUES
(NEW.description,
CASE NEW.recurrence
WHEN '1 WEEK' THEN
NEW.date + INTERVAL 7 DAY
WHEN '1 MONTH' THEN
NEW.date + INTERVAL 1 MONTH
WHEN '3 MONTH' THEN
NEW.date + INTERVAL 3 MONTH
ELSE
NULL
END,
NEW.userID, 0, NEW.recurrence);
END IF;
END;
Best of luck.