Question

IF (( SELECT param FROM changes WHERE type = 'uptime' AND website_id = 1 ORDER BY timestamp DESC LIMIT 1 ) != 'up' )
    INSERT INTO changes ( website_id, timestamp, type, param ) VALUES ( 1, NOW(), 'uptime', 'up' )
END IF;

This appears to be an incorrect syntax. How else can I make this work in a single query?

Answer 1

Why are you reading param record outside the query using IF instead of just adding it in the WHERE Condition? If you do it like this then you can just Insert the complete query, if the query returns something your data will be inserted, if your query returns nothing then nothing would be inserted:

INSERT INTO changes ( website_id, timestamp, type, param )
     SELECT 1, NOW(), 'uptime', 'up'
       FROM changes 
      WHERE type = 'uptime' AND website_id = 1 AND param != 'up' LIMIT 1