Null values in GreaterThan constraint raises error

[amontanez24]

Environment Details

Please indicate the following details about the environment in which you found the bug:

• SDV version: Any
• Python version: Any
• Operating System: Any

Error Description

If you create a GreaterThan constraint with columns that have null values, a ConstraintsNotMetError is raised.

Steps to reproduce

You can use the student_placements demo dataset to recreate this error.

student_placements = load_tabular_demo('student_placements')
gt_constraint = GreaterThan(
    low='start_date',
    high='end_date',
    handling_strategy='reject_sampling'
)
gc = GaussianCopula(constraints=[gt_constraint])
gc.fit(student_placements)

Running the same code above after dropping all rows in student_placements where start_date is NaN causes the error to go away.