如果存在，则为UPDATE Table，否则在Table中插入新行

Question

I have the following line of query in my stored procedure. The purpose of this stored procedure is if the website link is already in the table, it will update the existing one. If not it will record as new row from the other table' value.

CREATE DEFINER=`root`@`localhost` PROCEDURE `insert_diffmod_v2`( 
IN para_diffmod LONGTEXT, 
IN para_link LONGTEXT)
BEGIN

IF EXISTS (
    SELECT website_link FROM diffmod WHERE website_link=para_link
    )THEN 
    UPDATE diffmod
    SET diffmod_content=para_diffmod
    WHERE website_link= para_link; 

ELSE
    INSERT INTO diffmod(website_id,website_link)
    SELECT id,link
    FROM   site_html
    Where  link=para_link;

    UPDATE diffmod
    SET diffmod_content= para_diffmod
    where website_link = para_link;

END IF; 
END

Let's say www.google.com is already recorded. When I call like:

CALL myDB.insert_diffmod_v2('test','www.google.com'); 

there is no problem and it do update the existing record.

But when I called the link which is not in the record (let's say Yahoo) like

CALL  myDB.insert_diffmod_v2('test','www.yahoo.com');

it didn't insert as new record in the table. Can I know why ?

Answer 1

Insert in to on duplicate key update example

"$" are parameters and make website_id,website_link as unique

INSERT INTO diffmod SET
        website_id = (SELECT id FROM   site_html Where  link=@para_link),
        website_link= $para_link,
        diffmod_content=$para_diffmod
        ON DUPLICATE KEY UPDATE
        diffmod_content=$para_diffmod