An example in Pig of filtering data using conditional logic. Here a tuple is accepted if 'adj' equals either 'red' or 'blue'. As the number of conditions to check for grows this can be a pain to write.

filtering_with_or.pig

data = LOAD 'input' using PigStorage(',') AS (what:chararray, adj:chararray);
  
dump data;
-- (roses,red)
-- (violets,blue)
-- (sugar,sweet)
  
data2 = FILTER data BY adj == 'red' OR adj == 'blue';
  
dump data2;
-- (roses,red)
-- (violets,blue)