How can I stop a loop, depending on a existing value on a table? If it exists the loop continue, if it doesn´t exist, pass to the next date

[#1]

Hi, my problem consists in that I have a loop that recolect information of contactability of diferent clients by day, but the information is available only in certain day around the year, so the field "FEC_FECHA" (YEAR-MONTH-YEAR) is null in several dates around the year. For this cases I need that the script stop reading and pass to the next day inmediately, how can I do that? Here is the script:

I really need to do this filter, thats all. The dates that exists comes from the variable "FEC_FECHA". Thanks