What's is the maximum variables the sql "in" statement can handle

As said above

For instance WHERE In(var 1,var 2,var 3, ...开发者_开发技巧, var 5609,)

Any limits before it slows the machine down ?

I would say that if you have to ask then you're probably doing something wrong. :)

I don't believe there is a limit to the number of values in the list of the IN clause in MySQL, unlike the 1000 Oracle limit. I would verify this though by writing some sort of loop to build a really long 'IN' statement if you had a concern. Also, someone else asked this question and there wasn't a known limit.

Oracle 9i Maximum number of expressions in a list is 1000;

In Oracle (Verified only in 10g) it is 1000.

ORA-01795: maximum number of expressions in a list is 1000

With "limits", are you referring to a limitation in the the implementation, or something that will slow the query down? If it's the latter, the best answer is test it yourself.

MS SQL Server chokes at around 2000, MS SQL Compact has no limits (or I have not reached it yet, more than 2500).

Note: these are limits on parameters for queries.