The problem is that in order to establish a relationship between tables, they need to have a common value. It's like an MP3: it has a title, but it also has a musician (or band) that made it. So you could have two tables:
Artists:
ID ArtistName
1 Lana Del Ray
2 Coldplay
...
Because a band or artist is likely to produce more than one track, it makes sense to store them in their own table - otherwise you will be duplicating teh smae band name over, and over again.
And a Tracks table:
Tracks:
ID ArtistID TrackName
1 1 Gods and Monsters
2 1 Ride
3 2 Paradise
4 2 Fix You
...
And you can establish a
foreign key relationship between the Tracks and Artists on the Tracks.ArtistID and Artists.ID columns.
That lets you fetch related information:
SELECT a.ArtistName, t.TrackName
FROM Tracks t
JOIN Artists a ON t.ArtistID=a.ID
And that returns you:
Gods and Monsters Lana Del Ray
Ride Lana Del Ray
Paradise Coldplay
Fix You Coldplay
...
But if you don't have the "linking column" of the ArtistsID then there isn't a way to "connect" the two tables.
But...in your example, you don't want a "link" at all.
What you want to do is check each student grade against the minimum value the schools will accept and show which schools the student can go to.
That's just a simple SQL query:
SELECT Students.StudentName, Schools.SchoolName FROM Students, Schools
WHERE Students.Grade >= Schools.MinGrade
And that gives you:
StudentName SchoolName
qassem aaaaaaa
qassem bbbbbbb
qassem ccccccc
noor bbbbbbb
noor ccccccc
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