Question

I’m stuck with a SQL query (for SQL Server). I’m new to SQL and I’m not making much progress. I’ve created a test project to test tagging.

I have 3 tables as follows:

Monster: 
Name     Description              EatsPeople
Vampire  Pale, afraid of light    True
Ghost    See-through, annoying    False
Wraith   Green-ish, ugly, dumb    True

TagLookup:
Name    ID
Ghost   1
Ghost   2
Wraith  1

Tags:
ID    Text                      Value
1     Green                     green-skin
2     Screams like a banshee    banshee-call

I’m trying to select all monsters that have the tag value ‘green-skin’.

Answer 1

Assuming that Monsters.Name, Tags.Value, and the Name-ID combination in TagLookup are all unique:

SELECT m.Name, m.Description, m.EatsPeople
  FROM dbo.Monster AS m
  INNER JOIN dbo.TagLookup AS tl
    ON m.Name = tl.Name
  INNER JOIN dbo.Tags AS t
    ON t.ID = tl.ID
    AND t.Value = 'green-skin';