Alibabacloud, Database, Query Optimization, Sql, Relational Databases.
can be converted into inner join and early agg. As to the second query, it becomes an inequivalent condition of left join on after decorrelation, which is the same as cross join in cost. -- sql 1 SELECT t1.c1 FROM t1 WHERE t1.c2 > ( SELECT min(t2.c2) FROM t2 WHERE t2.c1 = t1.c1 ); -- sql 2 SELECT