Select all if condition empty

I'm sorry, in READ DATA, What is the best solution to select all values if variable is empty (or is x)?
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Now I have: Where Conditions table_field_name = {data:filtro_immagini}, and I would, if {data:filtro_immagini} is empty, select all...
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Thank you for reply.

Hi
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You have to use Behaviors/Data/Run Conditions
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When Add condition: {var:my_var} is empty o {data:one_data} is empty
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Bye