CREATE MATERIALIZED VIEW mv1 AS
   SELECT * FROM t 
   WHERE k IS NOT NULL AND c1 IS NOT NULL AND c2 IS NOT NULL
   PRIMARY KEY (c1, k, c2);

CREATE MATERIALIZED VIEW mv1 AS
  SELECT * FROM t 
  WHERE k IS NOT NULL AND c1 IS NOT NULL AND c2 IS NOT NULL
  PRIMARY KEY (v1, k, c1, c2);