php + mysql count consecutive data

[citricsquid]

I have a database of values and I want to work out how to display them if the values match a consecutive pattern.

 

For example, I might have the table "eggs" with the values "1", "2", "3", "4", "6", "7", "8", "9", "10". Now if I were to count these up I'd have 9 total values, this is good. What I want to do is ONLY count the values where they have another 2 consecutive values after them. So for example if the above pattern is what I'm using and I want to check for 2 consecutive values, the following would happen:

 

1 -> correct, it is followed by "2" and "3".

2 -> correct, it is followed by "3" and "4".

3 -> false, it is followed by "4" but no "5"

4 -> false, it is followed by "6", no"5".

6 -> correct, followed by "7" and "8".

7 -> correct, followed by "8" and "9".

8 -> correct, followed by "9" and "10".

9 -> false, followed by "10" but no "11".

 

and this would return the total of 7, because 7 of these values are followed by 2 consecutive numbers, therefore are correct.

 

So my question: How would I go about this? Would it be a matter of a single (albeit complex) mysql query or will I have to do some more advanced stuff after fetching the array? If it's the second I can do that myself, but I'd like to (hopefully) do it in a query!

 

So, any ideas?

[citricsquid]

So I've been thinking about it and I think it'd be possible to just do "where eggs = '$number' AND eggs ='$number+1' AND eggs ='$number+2'" (in proper query syntax). However let's say I need to do it for 100 different numbers, will this be a big hit on the database (performance wise)?