Question

I have two tables sturctured like so:

Posts Table
id
content

Meta Table
id
post_id
content
name

The posts table is the main parent that can have data from the meta table joined with it

Post Table
id   content
1    My first row

Meta Table
id   post_id  content   name
4    1        2011-5-5    date
5    1        My Heading  heading
6    2        2012-3-3    date
7    2        My Title    heading

How would I write a query to search for an entry in the posts table that contains meta data content of 2011-5-5 with a name of date and My Heading with a name of heading

I can get them individually

Select *
from posts, meta
WHERE post_id = posts.id
   AND (name='date' AND content='2011-5-5')

But as soon as I add a second criteria, it returns zero results, becuase we are asking the name field to be two different things

Select *
from posts, meta
WHERE post_id = posts.id
   AND (name='date' AND content='2011-5-5') 
   AND (name='heading' AND content='My Heading')

Any help would be greatly appreciated, Thanks!

Answer 1

You’ll need to join to the table twice:

SELECT *
FROM posts, meta m1, meta m2
WHERE posts.id=m1.post_id
AND posts.id=m2.post_id
AND m1.name="date" AND m1.content="2011-5-5"
AND m2.name="heading" AND m2.content="My Heading"