Php 在mysql中单次查询更新并选择内部连接

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';

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

更新mysql查询：

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

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

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您可以尝试以下查询：

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'
)

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这是更好的解决办法。