sql 去掉join,或者去掉order都很快，組合一起就慢了 具體該怎么去寫
select uwr.user_id userId,ld.prize_name prizeName,ld.type,uwr.create_time createTime
from user_winning_record uwr join lucky_draw ld
on uwr.draw_id=ld.id
where ld.type!=7
order by uwr.create_time
desc limit 20
uj5u.com熱心網友回復：
+---------------------+------------+---------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| user_winn | 0 | PRIMARY | 1 | id | A | 9772497 | NULL | NULL | | BTREE | | |
| user_winn | 1 | userid_idx | 1 | user_id | A | 814374 | NULL | NULL | YES | BTREE | | |
| user_winn | 1 | drawid_Idx | 1 | draw_id | A | 18 | NULL | NULL | YES | BTREE | | |
| user_winn | 1 | winning_count | 1 | user_id | A | 18 | NULL | NULL | YES | BTREE | | |
| user_winn | 1 | winning_count | 2 | type | A | 18 | 191 | NULL | YES | BTREE | | |
| user_winn | 1 | winning_count | 3 | create_time | A | 9772497 | NULL | NULL | YES | BTREE | | |
| user_winn | 1 | crtime | 1 | create_time | A | 9772497 | NULL | NULL | YES | BTREE | | |
+---------------------+------------+---------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
這表有990w資料 還有另一張 只有9條
uj5u.com熱心網友回復：
lucky_draw是9條的？小的表寫在前面on ld.id=uwr.draw_id
user_winning_record表建draw_id和create_time聯合索引
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標籤：MySQL
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