If you’re getting an error that reads “ERR numkeys should be greater than 0” in Redis, it’s probably because you’re specifying a wrong value for the first argument when calling the SINTERCARD command.

To fix this issue, make sure you’re passing a valid non-zero value that matches the number of keys you’re comparing.

Example of Error

Here’s an example of code that produces the error:

SINTERCARD set1 set2 set3

Result:

(error) ERR numkeys should be greater than 0

In this case, I passed the names of three keys, but I forgot to include the numkeys argument (which should be the first argument).

Solution

To fix the issue, be sure to include the numkeys argument, and make sure it’s a valid non-zero value that matches the number of keys you’re comparing.

Example:

SINTERCARD 3 set1 set2 set3

Result:

(integer) 2

Here, I provided the correct number of arguments and values and we got the desired result without error.