Question

我有一个小问题，有一个好的解决方案。我需要搜索更好的结果。

我有3个表，规则，含义和rule_meaning。 1规则可以有1个或更多含义。

这是

的结果

SELECT * FROM rule, rule_meaning, meaning WHERE rule_meaning.rule_id = rule.id AND rule_meaning.meaning_id = meaning.i

rule.id rule.name   rule.id meaning_id  meaning.id  meaning.name
1   RADIO - Ecouter   1        1          1          ACTIVER
1   RADIO - Ecouter   1        6          6          RADIO
2   LUMIERE Allumer   2        1          1          ACTIVER
3   RADIO + volume    3        6          6          RADIO
4   RADIO - volume    4        6          6          RADIO

当我搜索ACTIVER和RADIO我想只有RADIO - Ecouter（rule.id = 1）

我试过了

WHERE meaning.name = ACTIVER AND meaning.name = RADIO但没有结果
WHERE meaning.name = ACTIVER OR meaning.name = RADIO我有几个结果。

Answer 1

您想要选择具有ACTIVER和RADIO含义的规则。您可以使用聚合执行此操作：

select *
from rule
where id in
(
  select rule_id
  from rule_meaning 
  where meaning_id in (select id from meaning where name in ('ACTIVER', 'RADIO'))
  group by rule_id
  having count(*) = 2 -- both meanings
);

我更喜欢的另一种方法是使用EXISTS或IN分别查找每个值。我在这里展示它是因为它是如何处理任务的简单方法。

select *
from rule
where id in
(
  select rule_id
  from rule_meaning 
  where meaning_id = (select id from meaning where name = 'ACTIVER')
)
and id in
(
  select rule_id
  from rule_meaning 
  where meaning_id = (select id from meaning where name = 'RADIO')
);

Answer 2

您可能想要使用案例陈述，例如

    CASE WHEN WHERE meaning.name = ACTIVER AND meaning.name = RADIO
    THEN ....
    ELSE

但我认为你问的是

    WHERE meaning.name = ACTIVER AND rule.name = RADIO 
    AND rule.id = 1

选择更好的结果匹配

2 个答案: