我有两个MySQL安装，一个在Windows上使用Xampp，另一个在Mac上。机器的硬件类似 数据库是相同的，从DUMP文件导入每个MySQL。
我在这里发布了两个EXPLAINS EXTENDED：
EXPLAIN EXTENDED (ON MAC)
+----+--------------------+--------------+------------+--------+--------------------------+----------+---------+---------------------------------------+------+----------+---------------------------------------------------------------+
| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+--------------------+--------------+------------+--------+--------------------------+----------+---------+---------------------------------------+------+----------+---------------------------------------------------------------+
| 1 | PRIMARY | little_tasks | NULL | ref | post_id,meta_key | meta_key | 767 | const | 620 | 0.01 | Using where; Using temporary; Using filesort; Start temporary |
| 1 | PRIMARY | exp_baby | NULL | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.little_tasks.post_id | 12 | 0.39 | Using where |
| 1 | PRIMARY | certs | NULL | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.little_tasks.post_id | 12 | 0.39 | Using where |
| 1 | PRIMARY | radius | NULL | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.little_tasks.post_id | 12 | 3.00 | Using where |
| 1 | PRIMARY | exp_years | NULL | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.little_tasks.post_id | 12 | 1.00 | Using where |
| 1 | PRIMARY | remun_max | NULL | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.little_tasks.post_id | 12 | 1.00 | Using where |
| 1 | PRIMARY | edu | NULL | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.little_tasks.post_id | 12 | 1.00 | Using where |
| 1 | PRIMARY | start_date | NULL | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.little_tasks.post_id | 12 | 3.04 | Using where |
| 1 | PRIMARY | moment | NULL | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.little_tasks.post_id | 12 | 3.04 | Using where |
| 1 | PRIMARY | lat | NULL | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.little_tasks.post_id | 12 | 3.53 | Using where |
| 1 | PRIMARY | lon | NULL | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.little_tasks.post_id | 12 | 3.53 | Using where |
| 1 | PRIMARY | p | NULL | eq_ref | PRIMARY,type_status_date | PRIMARY | 8 | helpeeit_helpee2.little_tasks.post_id | 1 | 24.26 | Using where; End temporary |
| 3 | DEPENDENT SUBQUERY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | Impossible WHERE |
| 2 | SUBQUERY | spoken_lang | NULL | ref | post_id,meta_key | meta_key | 767 | const | 620 | 0.02 | Using where |
+----+--------------------+--------------+------------+--------+--------------------------+----------+---------+---------------------------------------+------+----------+---------------------------------------------------------------+
14 rows in set, 2 warnings (4 min 18,58 sec)
EXPLAIN EXTENDED (ON WINDOWS/XAMPP)
+----+--------------------+--------------+----------------+--------------------------+----------+---------+-------------------------------------+------+----------+----------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+--------------------+--------------+----------------+--------------------------+----------+---------+-------------------------------------+------+----------+----------------------------------------------+
| 1 | PRIMARY | radius | ref | post_id,meta_key | meta_key | 767 | const | 619 | 100.00 | Using where; Using temporary; Using filesort |
| 1 | PRIMARY | p | eq_ref | PRIMARY,type_status_date | PRIMARY | 8 | helpeeit_helpee2.radius.post_id | 1 | 100.00 | Using where |
| 1 | PRIMARY | exp_years | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.p.ID | 5 | 100.00 | Using where |
| 1 | PRIMARY | start_date | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.exp_years.post_id | 5 | 100.00 | Using where |
| 1 | PRIMARY | moment | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.start_date.post_id | 5 | 100.00 | Using where |
| 1 | PRIMARY | lat | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.radius.post_id | 5 | 100.00 | Using where |
| 1 | PRIMARY | lon | ref | post_id,meta_key | post_id | 8 | helpeeit_helpee2.lat.post_id | 5 | 100.00 | Using where |
| 8 | DEPENDENT SUBQUERY | edu | index_subquery | post_id,meta_key | post_id | 8 | func | 5 | 100.00 | Using where |
| 7 | DEPENDENT SUBQUERY | certs | index_subquery | post_id,meta_key | post_id | 8 | func | 5 | 100.00 | Using where |
| 6 | DEPENDENT SUBQUERY | little_tasks | index_subquery | post_id,meta_key | post_id | 8 | func | 5 | 100.00 | Using where |
| 5 | DEPENDENT SUBQUERY | exp_baby | index_subquery | post_id,meta_key | post_id | 8 | func | 5 | 100.00 | Using where |
| 4 | DEPENDENT SUBQUERY | remun_max | index_subquery | post_id,meta_key | post_id | 8 | func | 5 | 100.00 | Using where |
| 3 | DEPENDENT SUBQUERY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | Impossible WHERE |
| 2 | DEPENDENT SUBQUERY | spoken_lang | index_subquery | post_id,meta_key | post_id | 8 | func | 5 | 100.00 | Using where |
+----+--------------------+--------------+----------------+--------------------------+----------+---------+-------------------------------------+------+----------+----------------------------------------------+
14 rows in set, 1 warning (0.03 sec)
您可以自己查看执行时间 4分钟MAC ，而在WINDOWS / Xampp上 0.03秒
以下是查询：
SELECT DISTINCT p.ID,p.post_author, lat.meta_value AS lat, lon.meta_value AS lon, radius.meta_value AS radius, start_date.meta_value AS date_interval, moment.meta_value AS day_moment, exp_years.meta_value AS exp_years
FROM `hlp_posts` p
INNER JOIN hlp_postmeta AS lat ON (p.ID = lat.post_id AND lat.meta_key = "hlp_latitude")
INNER JOIN hlp_postmeta AS lon ON (p.ID = lon.post_id AND lon.meta_key = "hlp_longitude")
INNER JOIN hlp_postmeta AS radius ON (p.ID = radius.post_id AND radius.meta_key = "hlp_resume_range_distance")
INNER JOIN hlp_postmeta AS start_date ON (p.ID = start_date.post_id AND start_date.meta_key = "hlp_resume_date")
INNER JOIN hlp_postmeta AS moment ON (p.ID = moment.post_id AND moment.meta_key = "hlp_resume_availability")
INNER JOIN hlp_postmeta AS exp_years ON (p.ID = exp_years.post_id AND exp_years.meta_key = 'resume_years_of_exp' AND (exp_years.meta_value >= 4))
WHERE
p.post_type = 'babysitter'
AND p.post_status = 'publish'
AND (
p.ID IN (SELECT spoken_lang.post_id FROM hlp_postmeta AS spoken_lang WHERE spoken_lang.meta_key = 'wpjobus_resume_languages' AND (spoken_lang.meta_value LIKE '%Inglese%' AND spoken_lang.meta_value LIKE '%Francese%' AND spoken_lang.meta_value LIKE '%Spagnolo%' AND spoken_lang.meta_value LIKE '%Tedesco%'))
OR
p.ID IN (SELECT native_lang.post_id FROM hlp_postmeta AS native_lang WHERE native_lang.meta_key = 'wpjobus_resume_native_language' AND native_lang.meta_key = 'wpjobus_resume_native_language' AND (native_lang.meta_value = 'Inglese' AND native_lang.meta_value = 'Francese' AND native_lang.meta_value = 'Spagnolo' AND native_lang.meta_value = 'Tedesco'))
)
AND p.ID IN (SELECT remun_max.post_id FROM hlp_postmeta AS remun_max WHERE remun_max.meta_key = 'wpjobus_resume_remuneration' AND remun_max.meta_value <= 5)
AND p.ID IN (SELECT exp_baby.post_id FROM hlp_postmeta AS exp_baby WHERE exp_baby.meta_key = 'wpjobus_resume_skills' AND (exp_baby.meta_value LIKE '%i:0%' AND exp_baby.meta_value LIKE '%i:1%' AND exp_baby.meta_value LIKE '%i:2%' AND exp_baby.meta_value LIKE '%i:3%'))
AND p.ID IN (SELECT little_tasks.post_id FROM hlp_postmeta AS little_tasks WHERE little_tasks.meta_key = 'hlp_resume_little_tasks' AND (little_tasks.meta_value LIKE '%i:0%' AND little_tasks.meta_value LIKE '%i:1%' AND little_tasks.meta_value LIKE '%i:2%' AND little_tasks.meta_value LIKE '%i:3%' AND little_tasks.meta_value LIKE '%i:4%' AND little_tasks.meta_value LIKE '%i:5%' AND little_tasks.meta_value LIKE '%i:6%'))
AND p.ID IN (SELECT certs.post_id FROM hlp_postmeta AS certs WHERE certs.meta_key = 'hlp_resume_prof_edu' AND (certs.meta_value LIKE '%i:0%' AND certs.meta_value LIKE '%i:2%' AND certs.meta_value LIKE '%i:3%' AND certs.meta_value LIKE '%i:7%' AND certs.meta_value LIKE '%i:11%'))
AND p.ID IN (SELECT edu.post_id FROM hlp_postmeta AS edu WHERE edu.meta_key = 'hlp_resume_edu' AND (edu.meta_value >= 3))
ORDER BY `p`.`ID` DESC
我真的无法解释这是如何可能的。
答案 0 :(得分：0)