Oracle SQL: How to Use More Than 1000 Items Inside an in Clause

How to put more than 1000 values into an Oracle IN clause

Put the values in a temporary table and then do a select where id in (select id from temptable)

Oracle SQL: How to use more than 1000 items inside an IN clause

Not sure that using so many values in a IN() is that good, actually -- especially for performances.

When you say "the results are strange", maybe this is because a problem with parenthesis ? What if you try this, instead of what you proposed :

SELECT ...
FROM ...
WHERE ...
      AND (
          ep_codes IN (...1000 ep_codes...)
          OR  ep_codes IN (...200 ep_codes...)
      )

Does it make the results less strange ?

SQL IN Clause 1000 item limit

You should transform the IN clauses to INNER JOIN clauses.

You can transform a query like this one

SELECT  foo   
FROM    bar   
WHERE bar.stuff IN  
       (SELECT  stuff FROM asdf)

in a query like this other one.

SELECT  b.foo 
FROM    ( 
        SELECT  DISTINCT stuff 
        FROM    asdf ) a 
JOIN    bar b 
ON      b.stuff = a.stuff

You will also gain a lot of performance

Why oracle IN clause has limit of 1000 only for static data?

It's a restriction on any expression list:

A comma-delimited list of expressions can contain no more than 1000 expressions.

Why 1000? Presumably the implementation needs some kind of limit, and that probably seemed like more than enough. There may well be, or certainly may have been when that limit was set decades ago, a performance reason for the limit as well, particularly as the IN is converted to multiple OR statements by the optimiser in this case (which you can see if you look at the execution plan).

I'd struggle to come up with a reasonable scenario that needed to get anywhere near that, with fixed values that couldn't be derived from other data anyway as a subquery.

I suspect it's somewhat related to the logical database limits which say you can't have more than 1000 columns in a table, for instance; since an expression list is used in an insert statement to list both the columns and the values being inserted, the expression list has to be able to match that, but maybe has no reason to exceed it.

Speculation of course... without seeing the internals of the software you're unlikely to get a definitive answer.

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