Explain
explain慢查询SQL调优exists的实战
目录1 案发现场2 第一次优化3 第二次优化exists和not exists常用示例说明1.查询a表在b表中存在数据2.查询a表在b表中不存在数据3.查询时间最新记录4.exists替代distinct剔除重复数据总结最近我在公司优化了一些慢查询[详细]
2023-12-04 08:57 分类：数据库mySQL - How can I interpret my EXPLAIN results and optimize this query?
Looking to understand what my EXPLAIN results mean here, and to optimize this query and my tables as best as I can.[详细]
2023-04-12 07:58 分类：问答Improve MySQL Query with IN Subquery
I hava a table items and a table item_attributes. For simplicity let\'s say my table item has a column id and a column name.[详细]
2023-03-27 23:22 分类：问答MySQL command Explain ignore LIMIT?
I use MySQL server version 5.5.14 and now I am trying this simple SQL query with Explain command: EXPLAIN SELECT id, name, thumb FROM `twitter_profiles` LIMIT 10;[详细]
2023-03-21 19:11 分类：问答How to use mysql's EXPLAIN to look for possible problems
Stress testing a site & everything is breaking, obviously. Today\'s problem: WSOD on several pages. After a few hours I have narrowed the problem on one page down to this query (I hope): It used[详细]
2023-03-03 19:10 分类：问答MySQL Explain: what's causing 'Using temporary; Using filesort'
I\'m planning on creating a view using this SQL SELECT, but the explain for it shows it\'s using temporary and using filesort. I can\'t figure out what indices I need in order to fix this problem.[详细]
2023-03-02 12:10 分类：问答SELECT statement not using possible_keys
I have a table from a legacy system which does not have a primary key. It records transactional data for issuing materials in a factory.[详细]
2023-02-21 08:05 分类：问答mysql 5.1.37 query index not being used
I havea query that is performing poorly.Server version: 5.1.37-1ubuntu5.1 (Ubuntu) SELECT * FROM `influencers` WHERE (`influencers`.`twitter_id` = 86861293)LIMIT 1[详细]
2023-02-19 07:28 分类：问答Slow SQL query using Order By
I am far from a SQL guru and I am trying to execute: SELECT `apps`.* FROM `apps` INNER JOIN `similars`[详细]
2023-02-18 20:04 分类：问答MySQL explain shows that main table's indexes are not used at production server
I am trying to optimize the following modified MySQL query from OsCommerce: select distinct p.products_id, pd.products_name, m.manufacturers_name, s.specials_new_products_price from products p[详细]
2023-02-16 23:59 分类：问答
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