How many appearances does the word ID No. 2823 have in the Wikipedia page "Astre"?
Astre refers to title = 'Astre'; word ID No. 2823 refers to wid = 2823; appearances refers to pages_words_sampling.occurrences
SELECT SUM(T2.occurrences) FROM pages AS T1 INNER JOIN pages_words AS T2 ON T1.pid = T2.pid WHERE T1.title = 'Astre' AND T2.wid = 2823