MySQL IN clause: max number of arguments

You can also have the IN clause take the results of a query, such as:

SELECT * FROM table1 
WHERE table1.id IN 
    (
   SELECT id from table2
    )

That way, you don't need to generate a text string with all the possible values.

In mysql, you should be able to put as many values in the IN clause as you want, only constrained by the value of "max_allowed_packet".

http://dev.mysql.com/doc/refman/5.0/en/comparison-operators.html#function_in http://dev.mysql.com/doc/refman/5.0/en/server-system-variables.html#sysvar_max_allowed_packet

MariaDB (10.3.22 in my case) has a limit of 999 parameters to IN() before it creates a materialized temporary table, resulting in possibly much longer execution times. Depending on your indices. I haven't found a way to control this behaviour. MySQL 5.6.27 does not have this limit, at least not at ~1000 parameters. MySQL 5.7 might very well have the same "feature".

I ended up doing a series of where id = a or id = b ... but it also works fine by using series of where id in(a, b) or id in(c, d) ....