mysql 关联查询中 where 子句查询字段明明有索引为什么 explain 的时候没有？

UnrealEngine:

SELECT
cms.id uid, cms.username, cms.nickname, cms.type, count(*) num_member
FROM
yz_customer_service cms
INNER JOIN
yz_customer_service_member cm
ON
cms.id=cm.customer_service_id
WHERE
cms.create_time
BETWEEN ‘1695000000’ AND ‘1700496000’ GROUP BY cms.id;

create_time 有没有索引 type 一直都是 index

如果把 GROUP BY 去掉的话 type 直接 ALL 了……

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