如何优化这样的 SQL 语句？

Question

EXPLAIN SELECT COUNT(1),keyword FROM (
SELECT
    id,
    employee_id,
    keyword,
    jibie,
    creat_time
FROM
    lookup_record
GROUP BY
    employee_id,
    keyword
) temp GROUP BY keyword ORDER BY COUNT(1) DESC；

业务需求
employee_id 用户ID
keyword 查询关键词
统计一个关键词的查询人次，一个用户查询多次同一个关键词算一人次。

Answer 1

排重可以用count(DISTINCT expr)

SELECT
    count(DISTINCT employee_id) c,
    keyword
FROM
    lookup_record
GROUP BY
    keyword
ORDER BY
    c DESC

进一步优化可以在keyword上加索引