根据另一个表中的值从一个表中选择值

Question

I don't have my database populated yet, I'm still in the process of designing it. What I am doing is making a database based on a game, and I'm building a program to crawl through some data to fill the database. So, here's how the database is laid out.

Item Table
id, name, image

Stat Table
id, item_id, stat_name, stat_value

I have one of the stat names set to Class , and the stat value set to Warrior . I want to be able to select all items that have a stat of warrior selected. With my limited knowledge of SQL, this seems like it would require multiple queries, but I know I'm wrong.

I'm not great with joins, and I think that is where I would have to do it, but again, not so great with SQL. Any help would be greatly appreciated. Also, both the stat_name and stat_value would have to be queries. So stat_name='Class' stat_value='Warrior' .

Answer 1

SELECT DISTINCT i.*
FROM Item i
  JOIN Stat s
    ON i.id = s.id
WHERE s.stat_name = 'Class' 
  AND s.stat_value = 'Warrior'

This should work if I've interpreted your database idea.

I want to say that I think that your database design is flawed, your Stat table is going to be bloated and will be a pain to query with. Have you considered a table for each class?

Answer 2

     select i.*
       from item_table i
 inner join stat_table s
         on i.id = s.item_id
      where s.stat_name = 'Class' 
        and s.stat_value = 'Warrior'

if you don't need the id, just replace i.* with i.name, i.image

Answer 3

Not 100% if I follow, but I'll give it a shot. So you want to load rows from the Stat table and join the Item table?

SELECT * FROM Stat
    LEFT JOIN Item 
        ON Item.id = Stat.item_id 
WHERE Stat.stat_name='Class'
AND Stat.stat_value='Warrior'