The method loadColumnSchema determines a column as a boolean only if db type is 'BIT(1)'. The method loadColumnSchema for MS SQL is implemented in the right way. It considers both TINYINT(1) and BIT(1 ...
I am using Superset 4.1.3 for MySQL database, and I noticed that boolean fields are not displayed correctly in the Explore/SQL Lab table preview. Instead of showing true / false (or 1 / 0), Superset ...