Say I have a database with two tables: "food", and "whatToEat".
I query the "whatToEat" and find 3 rows:
id Food username
1 Apple John
2 Banana John
3 Milk Linda
If I want to get those from the "food" table, I can just do something like this i guess:
SELECT *
FROM food
WHERE username='John' AND typeOfFood = 'apple'
OR typeOfFood = 'Banana' OR typeOfFood = 'Milk'
... but is it possible to dynamically write this, since the "whatToEat" table will change all the time, or do I need a loop and query the "food" table one by one for each of the objects in "whatToEat"?
EDIT
The above is just an example, the real scenario is an online game. When it's a players turn in a game, he's put on the "matches_updated" table. This table just holds his name, and the id of the match (or matches since he can be in several at the same time). When a player recive an update, I would like to check if he have any matches that needs to be updated (query "matches_updated" table), and then pull the data and return to him from the "matches" table, where all the information is stored about the matches.
Example:
The player Tim query the "mathces_updated" table and find he have 2 new matches that needs to be updated:
match_id username
1 Tim
2 Tim
2 Lisa
1 John
3 John
... He now want to get the information about these matches, which is stored in the "matches" table:
match_id match_status player1Name Player1Score Player2Name Player2Score
1 1 John 123 Tim 12
2 1 Lisa 4 Tim 15
3 1 John 0 Lisa 0