没看懂,这个语句是想查什么呀???
explain analyze select count(*) from customer a where exists (select 1 from customer b where a.C_NATIONKEY=b.C_NATIONKEY);
没看懂,这个语句是想查什么呀???
explain analyze select count(*) from customer a where exists (select 1 from customer b where a.C_NATIONKEY=b.C_NATIONKEY);