Optimize inner join to semijoin when one side fields are not used post-join

Question

kaikalur opened this issue a year ago · 2 comments

SELECT T1.* FROM T1 INNER JOIN T2 ON T1.x=t2.y

can be turned into a semijoin:

SELECT T1.* FROM T1 WHERE T1.x IN (SELECT y FROM T2)

(maybe do DISTINCT on the rhs if T2 is gigantic)

Answer 1 · 2023-04-04T17:03:15.000Z

Answer 2 · 2023-04-04T17:04:19.000Z

Oops wrong repo