What does $$ sign means in mysql?
<p>In MySQL query, what does the $$ signify?</p>

<pre><code>DELIMITER $$
CREATE TRIGGER before_population_update
BEFORE UPDATE ON City
FOR EACH ROW BEGIN
INSERT INTO City_Changes
SET ACTION = ‘update’,
CityID = OLD.ID,
Population = OLD.Population,
User = USER(),
ChangedOn = NOW();
END $$
DELIMITER ;
</code></pre>