Specifically, I want to query word press posts based on N number of meta values which are in a key/value type of table.
I simply can't find a good example of a working query.
In plain English, the query would be like this.
Select all posts that city=Dallas, style=ranch, price between 100k and200k, po开发者_JAVA技巧ol=true
I may have more or less meta values I need to compare against.
For non-word press users, the meta values are in one table with each meta associated with a post Id from the posts table.
Ah, the joys of an EAV. In short, you need to do multiple subqueries or a crosstab.
Select ...
From Posts
Where post_id In (
Select post_id
From Meta
Where Attribute = 'City'
And Value = 'Dallas'
)
And post_id In (
Select post_id
From Meta
Where Attribute = 'Style'
And Value = 'Ranch'
)
And post_id In (
Select post_id
From Meta
Where Attribute = 'Price'
And Cast(Value As int) Between 100000 And 200000
)
And post_id In (
Select post_id
From Meta
Where Attribute = 'Pool'
And Value = 'True'
)
Here is another form which builds a crosstab. It is more compact but may not perform as well:
Select ...
From Posts As P
Join (
Select post_id
, Min( Case When Attribute = 'City' Then Value End ) As City
, Min( Case When Attribute = 'Style' Then Value End ) As Style
, Min( Case When Attribute = 'Price' Then Cast(Value As int) End ) As Price
, Min( Case When Attribute = 'Pool' Then Value End ) As Pool
From Meta
Where Attribute In('City','Style','Price','Pool')
Group By post_id
) As Attributes
On Attributes.post_id = P.post_id
Where Attributes.City = 'Dallas'
And Attributes.Style = 'Ranch'
And Attributes.Price Between 100000 And 200000
And Attributes.Pool = 'True'
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