What is the total number of words in page containing pair of word id "100" and "317"?
Pair is a relationship of two words: w1st and w2nd, where w1st is word id of the first word and w2nd is a word id of the second word; w1st = 100; w2nd = 317;
SELECT words FROM langs WHERE lid = ( SELECT lid FROM biwords WHERE w1st = 100 AND w2nd = 317 )