[英]Combining the results of two seperate SQL queries with 'OR'
框架:Rails 2.3.8数据库; PostgreSQL的
我目前有以下SQL语句(由Rails生成)
SELECT "outbreaks".* FROM "outbreaks" INNER JOIN "bacterial_agents" ON bacterial_agents.outbreak_id = outbreaks.id INNER JOIN "bacteria" ON "bacteria".id = "bacterial_agents".bacterium_id WHERE (bacteria.name ILIKE E'%VTEC O157%')
SELECT "outbreaks".* FROM "outbreaks" INNER JOIN "viral_agents" ON viral_agents.outbreak_id = outbreaks.id INNER JOIN "virus" ON "virus".id = "viral_agents".virus_id WHERE (virus.name ILIKE E'%NOROVIRUS%')
使用下表(我已经跳过了未使用的属性,并且布局/键的命名取决于Rails约定)
outbreaks
id
bacterial_agents
id
outbreak_id
bacterium_id
bacteria
id
name
viral_agents
id
outbreak_id
virus_id
viruses
id
name
任何想法,我如何将上面两个带有“ OR”条件的SQL语句结合起来,以选择与细菌表相关的爆发记录,其中细菌.name如“ VTEC O157”,或与病毒表相关的病毒。名称像“ NOROVIRUS”?
*编辑
关于Rails生成SQL的一些说明-当前输出以下SQL
SELECT "outbreaks".* FROM "outbreaks" INNER JOIN "bacterial_agents" ON bacterial_agents.outbreak_id = outbreaks.id INNER JOIN "bacteria" ON "bacteria".id = "bacterial_agents".bacterium_id INNER JOIN "viral_agents" ON outbreaks.id = viral_agents.outbreak_id INNER JOIN "viruses" ON "viral_agents".virus_id = "viruses".id WHERE ((bacteria.name ILIKE E'%VTEC O157%') AND (viruses.name ILIKE E'%NOROVIRUS%')) LIMIT 1
本质上,我想将前两个语句的组合结果输出为与上述语句类似的格式(用“ OR”条件代替“ AND”)。 但是,如果这不可能,我只需要编写一个作用域来处理SQL联合。
想想从下面的答复来看,我将结合两个单独的声明,加油:)
我认为您将SQL联合运算符与OR混淆,无法将两个查询的返回值结合在一起。
OR用于管理语句的WHERE部分中的条件,而union用于将一个查询附加到另一个查询。
您应该注意,仅当两个查询具有相同的域时,联合才有效。 通过快速查看您的查询,它应该完全符合您的想法。
尝试这个:
SELECT "outbreaks".* FROM "outbreaks" INNER JOIN "bacterial_agents" ON bacterial_agents.outbreak_id = outbreaks.id INNER JOIN "bacteria" ON "bacteria".id = "bacterial_agents".bacterium_id WHERE (bacteria.name ILIKE E'%VTEC O157%')
UNION
SELECT "outbreaks".* FROM "outbreaks" INNER JOIN "viral_agents" ON viral_agents.outbreak_id = outbreaks.id INNER JOIN "virus" ON "virus".id = "viral_agents".virus_id WHERE (virus.name ILIKE E'%NOROVIRUS%')
只需在查询之间放置一个UNION ALL
SELECT "outbreaks".*
FROM "outbreaks"
INNER JOIN "bacterial_agents" ON bacterial_agents.outbreak_id = outbreaks.id
INNER JOIN "bacteria" ON "bacteria".id = "bacterial_agents".bacterium_id
WHERE (bacteria.name ILIKE E'%VTEC O157%')
UNION ALL
SELECT "outbreaks".*
FROM "outbreaks"
INNER JOIN "viral_agents" ON viral_agents.outbreak_id = outbreaks.id
INNER JOIN "virus" ON "virus".id = "viral_agents".virus_id
WHERE (virus.name ILIKE E'%NOROVIRUS%')
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