Difference between Top and Limit Keyword in SQL

Question

A quick Question. Suppose I have the following two queries:

SELECT TOP 2 * FROM Persons; 

and

SELECT * FROM Persons limit 2; 

I want to know the difference between the execution of the above 2 queries? Basically, I want to know when should I use the limit keyword and when it is appropriate to use the top keyword. Also, How does the database return results based on the above 2 queries.

Answer 1

If you are using SQL Server use TOP if you are using MySQL or Postgres use Limit!

AFAIK there is no product that currently supports both. Here's one list of current implementations and here's another (covers more products but in less detail)

Answer 2

As stated in my comment for Martin Smith's answer above, there are products that support both, LIMIT and TOP (as you can see here). The difference is that TOP only selects the first n records, but LIMIT allows the definition of an offset to retrieve a specific range of records:

SELECT * FROM ... LIMIT 5 OFFSET 10 

This statement selects the first 5 records, after skipping 10 records and this isn't possible with TOP.

The example I posted is only checked against the DBS I linked above. I didn't check a SQL standard, because of a lack of time.