我有以下查询非常慢（2.9 seg）：
SELECT post_id
FROM ap_props
LEFT JOIN ap_moneda
ON ( ap_props.rela_moneda = ap_moneda.id_moneda )
LEFT JOIN wp_posts
ON ( ap_props.post_id = wp_posts.id )
WHERE 1 = 1
AND wp_posts.post_status = "publish"
AND rela_inmuebleoper = "2"
AND rela_inmuebletipo = "1"
AND (( approps_precio * Ifnull(moneda_valor, 0) >= 2000
AND approps_precio * Ifnull(moneda_valor, 0) <= 6000 ))
AND rela_barrio IN ( 6, 23085, 23086, 23087,
7, 23088, 23089, 23090,
23091, 23092, 26, 23115,
23116, 23117, 23118, 23119,
23120, 32, 43, 23123,
23124, 23125 )
AND ( post_id IS NOT NULL );
2.90808200
分析显示：
+--------------------------------+----------+
| Status | Duration |
+--------------------------------+----------+
| starting | 0.000132 |
| checking query cache for query | 0.000135 |
| Opening tables | 0.000023 |
| System lock | 0.000009 |
| Table lock | 0.000033 |
| init | 0.000074 |
| optimizing | 0.000030 |
| statistics | 0.001989 |
| preparing | 0.000028 |
| executing | 0.000007 |
| Sending data | 2.905463 |
| end | 0.000015 |
| query end | 0.000005 |
| freeing items | 0.000055 |
| storing result in query cache | 0.000013 |
| logging slow query | 0.000009 |
| logging slow query | 0.000055 |
| cleaning up | 0.000007 |
+--------------------------------+----------+
和解释：
+----+-------------+-----------+-------------+---------------------------------------------------------------------+-------------------------------------------+---------+---------------------------+-------+-------------------------------------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-----------+-------------+----------------------------------------------------------------------+-------------------------------------------+---------+---------------------------+-------+-------------------------------------------------------------------------+
| 1 | SIMPLE | ap_props | index_merge | idx_post_id,idx_relabarrio,idx_relainmuebleoper,idx_relainmuebletipo | idx_relainmuebleoper,idx_relainmuebletipo | 5,5 | NULL | 58114 | Using intersect(idx_relainmuebleoper,idx_relainmuebletipo); Using where |
| 1 | SIMPLE | ap_moneda | ALL | NULL | NULL | NULL | NULL | 3 | Using where |
| 1 | SIMPLE | wp_posts | eq_ref | PRIMARY | PRIMARY | 8 | metaprop.ap_props.post_id | 1 | Using where |
+----+-------------+-----------+-------------+----------------------------------------------------------------------+-------------------------------------------+---------+---------------------------+-------+-------------------------------------------------------------------------+
有关如何改进它的任何想法？ ap_props和wp-posts中的条目总数约为400.000。 ap_moneda只有5个条目。
我尝试删除IN子句，但以下显示了相同的性能结果：
SELECT post_id from ap_props left join ap_moneda on (ap_props.rela_moneda = ap_moneda.id_moneda) left join wp_posts on (ap_props.post_id = wp_posts.ID) where 1=1 AND wp_posts.post_status = "publish" AND rela_inmuebleoper = "2" AND rela_inmuebletipo = "1" AND ( ( approps_precio * ifnull(moneda_valor,0) >= 2000 AND approps_precio * ifnull(moneda_valor,0) <= 6000) ) AND (rela_barrio=6 OR rela_barrio=23085 OR rela_barrio=23086 OR rela_barrio=23087 OR rela_barrio=7 OR rela_barrio=23088 OR rela_barrio=23089 OR rela_barrio=23090 OR rela_barrio=23091 OR rela_barrio=23092 OR rela_barrio=26 OR rela_barrio=23115 OR rela_barrio=23116 OR rela_barrio=23117 OR rela_barrio=23118 OR rela_barrio=23119 OR rela_barrio=23120 OR rela_barrio=32 OR rela_barrio=43 OR rela_barrio=23123 OR rela_barrio=23124 OR rela_barrio=23125) AND (post_id IS NOT NULL);
2.91080400
非常感谢你的帮助！
编辑：
目前的指数是：
+----------+------------+----------------------+--------------+-------------------+-----------+-------------+----------+--------+------+------------+---------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+----------+------------+----------------------+--------------+-------------------+-----------+-------------+----------+--------+------+------------+---------+
| ap_props | 0 | PRIMARY | 1 | approps_origen | A | 10 | NULL | NULL | | BTREE | |
| ap_props | 0 | PRIMARY | 2 | approps_id_aviso | A | 452098 | NULL | NULL | | BTREE | |
| ap_props | 1 | idx_status | 1 | approps_status_db | A | 3 | NULL | NULL | YES | BTREE | |
| ap_props | 1 | idx_fecha | 1 | approps_fecha | A | 64585 | NULL | NULL | YES | BTREE | |
| ap_props | 1 | idx_post_id | 1 | post_id | A | 452098 | NULL | NULL | YES | BTREE | |
| ap_props | 1 | idx_relabarrio | 1 | rela_barrio | A | 2457 | NULL | NULL | YES | BTREE | |
| ap_props | 1 | idx_relainmuebleoper | 1 | rela_inmuebleoper | A | 6 | NULL | NULL | YES | BTREE | |
| ap_props | 1 | idx_relainmuebletipo | 1 | rela_inmuebletipo | A | 17 | NULL | NULL | YES | BTREE | |
+----------+------------+----------------------+--------------+-------------------+-----------+-------------+----------+--------+------+------------+---------+
FYI F通过添加新索引idx_approps_precio并通过添加“使用索引（idx_relabarrio，idx_approps_precio）”来强制它来修复它
答案 0 :(得分：0)
如果在加入表而不是第一次加入时放置AND然后过滤结果集
试一试
SELECT post_id
FROM ap_props
LEFT JOIN ap_moneda
ON ( ap_props.rela_moneda = ap_moneda.id_moneda AND `table`.rela_inmuebleoper = "2" AND `table`.rela_inmuebletipo = "1" )
LEFT JOIN wp_posts
ON ( ap_props.post_id = wp_posts.id AND wp_posts.post_status = "publish")
WHERE rela_barrio IN ( 6, 23085, 23086, 23087,
7, 23088, 23089, 23090,
23091, 23092, 26, 23115,
23116, 23117, 23118, 23119,
23120, 32, 43, 23123,
23124, 23125 )
AND (( approps_precio * Ifnull(moneda_valor, 0) >= 2000
AND approps_precio * Ifnull(moneda_valor, 0) <= 6000 ))
AND ( post_id IS NOT NULL );
我已将这两个条件放在连接中，不确定表名，因此您应该注意它table.rela_inmuebleoper = "2" AND table.rela_inmuebletipo = "1"提供正确的表名。并检查并为列提供适当的索引