Issue Summary

A table with a boolean field is being displayed as "false" when the value that was inserted is null.

source database is Redshift

reDash 1 ( works as expected)

reDash 4 - displays the null field as false

Steps to Reproduce

1. Create a new table with a boolean field:

create table boolean_test (my_field boolean);

2. insert values into the table

INSERT INTO boolean_test VALUES (true);
INSERT INTO boolean_test VALUES (false);
INSERT INTO boolean_test VALUES (null);

3. run the query in reDash 4:

select * from boolean_test

Any other info e.g. Why do you consider this to be a bug? What did you expect to happen instead?
I expect the same results as in reDash v1. querying this type of field does not necessarily should evaluate to false when null - i.e no data was given by this field

Technical details:

• Redash Version: 4.0.0
• Branch: master
• From PR: Fixes #2488 #2489
• Browser/OS: chrome
• How did you install Redash: docker.