count()

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SELECT COUNT(*),0,0 FROM AGROUP BYUNION ALLSELECT 0,COUNT(*),0 FROM BGROUP BYUNION ALLSELECT 0,0,COUNT(*) FROM CGROUP BYSELECT SUM(A),SUM(B),SUM(C)  FROM (SELECT COUNT(*) A,0 B,0 C           FROM X      GROUP BY           UNION ALL        SELECT 0 A,COUNT(*) B,0 C           FROM B      GROUP BY           UNION ALL        SELECT 0 A,0 B,COUNT(*) C         FROM C      GROUP BY)                  SELECT COUNT(*) A,0 B,0 C           FROM X      GROUP BY