The first thing to do is to learn from this. When you are asking a question, you need to follow that all wonderful advice (written somewhere) - and make sure that your future questions are clear as a bell. Even if it seems impossible, put that super obvious statement in there so there cannot be confusion in what you are asking.
Secondly, don't delete the question - folks put time in to answer it, and it might well help others on the site. If you think you might salvage it by editing and getting other replies, do so (Probably better to leave the original content there and add a rather big EDIT: line to the bottom) though so that the answers given don't attract downvotes (they were right at the time).
If you think it cannot be salvaged through editing to read how you meant it, I would suggest editing it ever so slightly, so the next person who reads the question sees the answers that fit that question. And post a new question.
Edit: On looking through the three answers provided, they do actually answer your question:
I want to return rows that both have a certain value in a certain column. For example in tables Carpets and Curtains, I want to get the ids of rows where the colour is 'light yellow'.
You have an example of a union with a where clause on each - this will output the data from each table on a separate row of your result (the same output as an intersect)
And you have two examples of a join where you can return the data from both tables in a single row of data. You don't need to edit this question, they have given you the right info and read it correctly. (Again, this will return the same data as an intersect in your case).
If anything, I would suggest that you include your code - or post your own answer to the question in this case. Looking at them - they will all be right.
I went through and tried to give you a pretty thorough explanation of the other answers with examples in a little database I made just to answer your question :)
INTERSECT
ids from tables calledCarpets
andCurtains
?