sql 过滤多列

Question

树：

id name
1  apple
2  aspen

树属性类别：

id categorie
1  leafColour
2  trunkColour

树属性：

id tree_id attribute tree_attribute_categorie_id
1  1       brown     1
2  1       brown     2
3  2       green     1
4  2       brown     2

sql 语句如何过滤如下（属性和 tree_attribute_categorie_id）：

[[brown and 1] OR [red and 1]] AND [[brown and 2] OR [green and 2]] = return apple tree
[[brown and 1] OR [green and 1]] AND [[brown and 2] OR [green and 2]] = returns both trees

Answer 1

您可以使用group by并having ：

select t.*
from tree t
inner join treeattributes ta on ta.tree_id = t.id
group by t.id
having max(ta.tree_attribute_categorie_id = 1 and ta.attribute in ('brown', 'red')) = 1
   and max(ta.tree_attribute_categorie_id = 2 and ta.attribute in ('brown', 'green')) = 1

这与您问题中的第一个过滤器规范相匹配。 第二个规范的having子句如下所示：

having max(ta.tree_attribute_categorie_id = 1 and ta.attribute in ('brown', 'green')) = 1
   and max(ta.tree_attribute_categorie_id = 2 and ta.attribute in ('brown', 'green')) = 1

如果您想按属性名称而不是按属性 id 进行过滤，您可以再添加一个连接，并调整having子句：

select t.*
from tree t
inner join treeattributes ta on ta.tree_id = t.id
inner join treeattributecategori tag on tag.id = ta.tree_attribute_categorie_i
group by t.id
having max(tag.categorie = 'leafColour' and ta.attribute in ('brown', 'red')) = 1
   and max(tag.categorie = 'trunkColour' and ta.attribute in ('brown', 'green')) = 1