text: Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
  ### Context:
  CREATE TABLE review (u_id VARCHAR); CREATE TABLE useracct (u_id VARCHAR)
  ### Question:
  Find the number of users who did not write any review.
  ### Answer:
  SELECT COUNT(*) FROM useracct WHERE NOT u_id IN (SELECT u_id FROM review)