Mysql syntax error when creating trigger on delete

Question

I am having an issue creating a trigger in my database. The idea is that, when a song is removed from a playlist, the corresponding row is deleted from the table playlistcancion . The idea of the trigger is that it removes the time of the deleted song from the total time of the playlist.

view name: pycs (shows songs of corresponding playlists)
column name | SongID | playlistID | Playlist | songName | Duration
data type   | INT    | INT        | varchar  | varchar  | TIME 

table name: playlistcancion (keeps track of which songs are in which playlists)
column name | songID | playlistID 
data type   | INT    | INT   

table name: playlists (playlist data and creators userID)
column name | playlistID| userID  | Followers  | Title  | TotalDuration
data type   | INT       | INT     | INT        | varchar| TIME 

Here is my trigger query:

CREATE TRIGGER remove_time
AFTER DELETE ON playlistcancion
FOR EACH ROW 
    DECLARE dur TIME;
    SELECT Duration INTO dur FROM pycs WHERE playlistID = OLD.playlistID AND songID = OLD.songID;
    UPDATE playlists SET TotalDuration = SEC_TO_TIME(TIME_TO_SEC(TotalDuration) - TIME_TO_SEC(dur))
    WHERE playlistID = OLD.playlistID;

The error i am getting is: MySQL said: #1064 - There's something wrong with your syntax near 'DECLARE dur TIME; SELECT Duration INTO dur FROM pycs WHERE playlisID = OLD.pla' in line 1 I am using phpMyAdmin to create the trigger. Thanks in advance.

Answer 1

Adding BEGIN and END resolved that error you are getting.

CREATE TRIGGER remove_time
AFTER DELETE ON playlistcancion
FOR EACH ROW BEGIN
    DECLARE dur TIME;
    SELECT Duration INTO dur FROM pycs WHERE playlistID = OLD.playlistID AND songID = OLD.songID;
    UPDATE playlists SET TotalDuration = SEC_TO_TIME(TIME_TO_SEC(TotalDuration) - TIME_TO_SEC(dur))
    WHERE playlistID = OLD.playlistID;
    END;

If you face more issue better post with insert script of all the tables involved in the triggers.

Answer 2

Combine your trigger into single-statement form:

CREATE TRIGGER remove_time
AFTER DELETE 
ON playlistcancion
FOR EACH ROW 
UPDATE playlists 
SET TotalDuration = SEC_TO_TIME(   TIME_TO_SEC(TotalDuration) 
                                 - TIME_TO_SEC(SELECT Duration 
                                               FROM pycs 
                                               WHERE playlistID = OLD.playlistID 
                                                 AND songID = OLD.songID))
WHERE playlistID = OLD.playlistID;

Now it does not need in intermediate variable, BEGIN-END block and DELIMITER reassign.