How many times you can write Select Inside Select query in Mysql?

Question

When I was studying MySQL I have been asked by my Teacher to find out that how many times we can write Select query inside Select query

At that time I found the answer practically.

Answer 1

select in a select is really slow and shouldn't be used, unless there is no other alternative.

Try using joins to solve your problem, they work 90% of the time where you want to use a select in an other select...

Answer 2

In theory it should be infinite, nested queries are allowed at multiple levels. In reality, you are limited by memory and hopefully common sense.