We have a statistical table for daily sales of January 2022:

Now we want to find out the data of date where the previous and next day’s sales are both more than 500 lower than that of the date:

=spl("=E(?1).select(Sales[-1]<Sales-500 && Sales[1]<Sales-500)",A1:B32)

Sales[-1] represents the value of the column Sales of the previous row, and Sales[1] represents the value of the column Sales of the next row.
 

esProc Desktop and Excel Processing
6.7 Filter by multiple conditions
6.9 Take values of adjacent rows in same group (search & filter within adjacent intervals)