creating MySQL Trigger to insert into second table

I'm trying to setup a trigger to insert a sum into a second table after insert of the first table.

The tables are:

• First Table Name: likes

• Fields: feedid

• Second Table Name: like_count

• Fields: total, feedid

After insert on likes table, I need to check if the feedid exists in table like_count. If not just insert it with total of 1. If it does exists, I need to update like_count.total to increment by one where likes.feedid = like_count.feedid

You can use MySQL INSERT ... ON DUPLICATE KEY syntax to simplify the logic of the trigger.

For this to work, feedid must be a unique column in table likes_count (either it is the primary key of the column, or you need to create a UNIQUE constraint on it). Then:

DELIMITER //
CREATE TRIGGER update_likes_count
AFTER INSERT ON likes FOR EACH ROW
BEGIN
    INSERT INTO likes_count (feed_id, total) VALUES (NEW.feedid, 1)
    ON DUPLICATE KEY UPDATE total = total + 1;
END;
//
DELIMITER;