Database: scholar
Question: How many papers did David M. Blei publish at AISTATS ?
SQL:
SELECT DISTINCT COUNT ( t3.paperid ) FROM venue AS t4 JOIN paper AS t3 ON t4.venueid  =  t3.venueid JOIN writes AS t2 ON t2.paperid  =  t3.paperid JOIN author AS t1 ON t2.authorid  =  t1.authorid WHERE t1.authorname  =  "David M. Blei" AND t4.venuename  =  "AISTATS";