MySQL 相关项目
› MariaDB
› Drizzle
参考文档
› http://mysql-python.sourceforge.net/MySQLdb.html
有个表有 title 和 context 字段，搜索的时候使用这个 SQL 匹配
SELECT * FROM post WHERE title LIKE "%google%" OR context LIKE "%google%" LIMIT 10
现在希望先匹配 title 字段，然后再匹配 context 字段……也就是结果 title 匹配在前，context 匹配在后
如果 title 足够 10 个的话就不用再匹配 context 了
搜了搜几乎没啥帮助（也有可能我不知道要怎么描述这个情况……），于是只能来问问了（
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1
ywcjxf1515 Jul 26, 2019  1
一个未优化的思路：
select * from( select *,1 as status from ( select * from (SELECT * FROM post WHERE title like '%Linux%' limit 10) as a except select * from (SELECT * FROM post WHERE context like '%算法%' limit 10) as b) as c union select *,2 as status from ( select * from (SELECT * FROM post WHERE context like '%算法%' limit 10) as d union select * from (SELECT * FROM post WHERE title like '%Linux%' limit 10) as e) as f union select *,3 as status from ( select * from (SELECT * FROM post WHERE context like '%算法%' limit 10) as g except select * from (SELECT * FROM post WHERE title like '%Linux%' limit 10) as i ) as j )as s order by status limit 10; 如果你使用 mysql 8.0，会容易很多。我觉得还是读两次数据库在内存中计算吧。 |
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