Hello @Yhaizley RV , you can do it with Formulas:

Hello, thank you for your help.

But I must not only compare with a date, i have a list of dates that are stored in the database and that when bringing them to nintex are in a collection.

That is to say, if I select the date 03/06/2024 in the form, it must look for me in that collection of dates if it has already been taken or not.

Thank you
 

Hello @Yhaizley RV ,

I see the problem.

Because NAC always passes the date at a UTC datetime to SQL, it will be very difficult to implement this directly on a Table based Data Source Variable. So one way I could suggest is to use a SQL Stored Procedure which takes two date strings as input.

You then create a Data Source on the SPROC and a DSV on your Form where you pass in formatted dates and do a test to see if any rows are returned.

Hi @Yhaizley RV 
Did this response solve your question?

Hello, thank you for all your help
At the moment you gave me the idea of ​​doing this, it wouldn't complete the whole problem but it improves the system

What I did was create a source data that would bring me all the start date and end date that I had stored in the database. 

I converted to string the collection of all the dates of start date and end date that the source data brings me

I had to format the end date and start date of the form to match the collection.
 

Then, create this rule that what it does is compare if the date selected in the form is in the collection of data that it is bringing me

If the rule is completed it shows me this error in the form

 

But now I need the dates between the selected dates to also appear as not possible to take. 

It would be very helpful and easy if there was the between dates option.