Question

I am writing a stored procedure where I have an input parameter called my_size that is an INTEGER. I want to be able to use it in a LIMIT clause in a SELECT statement. Apparently this is not supported, is there a way to work around this?

# I want something like: SELECT * FROM some_table LIMIT my_size;  # Instead of hardcoding a permanent limit: SELECT * FROM some_table LIMIT 100; 

Answer 1

A search turned up this article. I’ve pasted the relevant text below.

Here’s a forum post showing an example of prepared statements letting you assign a variable value to the limit clause:

http://forums.mysql.com/read.php?98,126379,133966#msg-133966

However, I think this bug should get some attention because I can’t imagine that prepared statements within a procedure will allow for any procedure-compile-time optimizations. I have a feeling that prepared statements are compiled and executed at the runtime of the procedure, which probaby has a negative impact on efficiency. If the limit clause could accept normal procedure variables (say, a procedure argument), then the database could still perform compile-time optimizations on the rest of the query, within the procedure. This would likely yield faster execution of the procedure. I’m no expert though.