I have a question about joining tables and how long they take to process.

It's not directly a problem, but rather that someone could shed some light on why one method takes far longer then another.

Why does this top method take 90 seconds to complete while the bottom method takes less than a second?

```
SELECT *
FROM Cables C
LEFT JOIN Fibres F on C.OID = F.OID1 or C.OID = F.OID2

SELECT *
FROM Cables C
LEFT JOIN Fibres F  on C.OID = F.OID1
LEFT JOIN Fibres F2 on C.OID = F2.OID2

```