单个查询更新并在mysql中选择内连接

Question

如何组合这两个查询？

选择mysql查询：

SELECT avg(b.averageRating) 
FROM review a INNER 
JOIN review b ON b.institudeId=a.institudeId 
WHERE a.reviewId='3';

更新mysql查询：

update table institutions 
set averageRatings=avg(b.averageRating) 
where id=a.institudeId;

Answer 1

您可以尝试此查询：

UPDATE institutions SET institutions.overallRatings = (
  SELECT avg(b.averageRating) 
  FROM review a 
  INNER JOIN review b ON b.institudeId=a.institudeId WHERE a.reviewId='3'
) 
WHERE institutions.id = (
  SELECT institudeId FROM review WHERE reviewId='3'
)