このレッスンは、現在英語のみです。
Why is this query slow?
A query that takes 2 ms on a thousand rows can take 2 seconds on ten million. Indexes fix that, and EXPLAIN shows you whether they are actually being used.
このレッスンは、現在英語のみです。
A query that takes 2 ms on a thousand rows can take 2 seconds on ten million. Indexes fix that, and EXPLAIN shows you whether they are actually being used.