force_index优化sql

SELECT
NAME,
count(1) c
FROM
USER
WHERE
time BETWEEN "2015-07-06"
AND "2015-07-07"
GROUP BY
NAME
HAVING
c > 20
ORDER BY

DESC;

这条sql 用到的联合索引 in_time_name

SELECT
NAME,
count(1) c
FROM
USER force index (ind_time)//强制索引
WHERE
time BETWEEN "2015-07-06"
AND "2015-07-07"
GROUP BY
NAME
HAVING
c > 20
ORDER BY
DESC;

指令每条sql用哪个索引  避免mysql优化器用到一个低效索引