limiting the rows to where the sum a column equals a certain value in MySQL

Question

I want to write a query which returns all rows until the sum of one of the columns value reaches a certain value.

For example in the table below:

Answer 1

This one outperforms all.

SET @runningTotal=0;
SELECT
  O.Id,
  O.Type,
  O.MyAmountCol,
  @runningTotal + O.MyAmountCol as 'RunningTotal',
  @runningTotal := @runningTotal + O.MyAmountCol
FROM Table1 O
HAVING RunningTotal <=7;

SQL Fiddle

Take a look at execution plans for both queries.