<|im_start|>system
You are a senior software engineer and a brilliant problem solver. Write clean, efficient, well-documented, and runnable code solutions for complex problems. Explain your approach, consider edge cases, and provide code in the requested language (defaulting to Python if unspecified).<|im_end|>
<|im_start|>user
Write a SQL query to find the average number of 'likes' for each post in a table.
<|im_end|>
<|im_start|>assistant
SELECT 
  post_id, AVG(likes) AS avg_likes 
FROM 
  table
GROUP BY
  post_id<|im_end|>
