We now have a Dropdown - multiselect control where the field in the dataset has over 1,000 distinct values so the user will need to search for the values to change the selection. Since our Dataset is the result of multiple tables (one primary, the rest left joined), some fields contain NULL.
On other controls, the user can choose to deselect NULL in order to simulate an inner join or select it for a left join.
How do we search for NULL in a Dropdown - multiselect control with over 1,000 values? NULL, null, and ââ do not work and ââ generates an error (A calculated field contains invalid syntax. Correct the syntax and try again.). I did confirm NULL is in the control by filtering down with other controls connected with relevant values, but this is not a realistic way for the user to access the NULL value in this control.
Hello @MikeB, thank you for providing so much detail on this issue. Sometimes when I am using multi value parameters in a control, I will see a NULL value denoted as empty string instead of NULL. I am not sure it would work if you searched that either though.
I know it wouldnât be ideal, but if the control has a list of string values, maybe you could create a calculated field on the dataset that would return a string value of NULL instead of an actual null value. That might be the best work-around to bypass this limitation and make it searchable in the control.
Hello @DylanM, Thank you for the reply. In our data, Iâve been seeing âEmpty stringâ when we have an actual empty string and NULL when we have a null value. I tried searching for empty string in the control with over 1,000 values and nothing show up.
The odd thing is that in controls with < 1000 items, I can search for NULL, or null, etc. to find the NULL value and Empty string, empty, string etc. to find the Empty string value. For some reason these searches donât work when the control has over 1,000 values. I tried searching for * and scrolling/paging through the values and NULL is not there. It only shows up when I filter on other controls, reducing the number of values in this control via relevant values⌠I will put in a support ticket to see if they have any suggestions or if this is something that can be fixed.
Thank you for the work-around suggestion. I will do some experimentation to see if I can come up with a solution that will work for now.
Hello @MikeB, based on the issue you are facing, and this other question in the community, it seems like you are specifically hitting a limitation related to multi-value parameters and functionality with NULLs.
I was led to this conclusion because if you wanted to check a multi-value parameter for the select all option in a calculated field, you check if it is returning a NULL value: in(NULL, ${Parameter})
I would imagine, the error you are experiencing would be eliminated if you switched from a multi-value to a single value option. If that is not a possibility, switching a true NULL value for a string NULL may be the best work-around for you at the moment.
I would also recommend filing a case with AWS Support where we can dive into the details so that we can help you further. Here are the steps to open a support case. If your company has someone who manages your AWS account, you might not have direct access to AWS
Support and will need to raise an internal ticket to your IT team or whomever manages your AWS account. They should be able to open an AWS Support case on your behalf. Hope this helps!
Hello @MikeB, since we have not heard back from you with any remaining questions on this issue, I will tag this topic accordingly and archive it for our support team. I believe there are some bugs involving NULLs in multi-value parameters, so I will make sure the appropriate team has information on this issue.