self.check_sample("select sample( c1 ,3 ),c2,c3,c4,c5 from t1 where c1 between 1 and 10","select c1,c2,c3,c4,c5 from t1 where c1 between 1 and 10")
self.check_sample("select sample( c1 ,3 ),c2,c3,c4,c5 from stb1 where c1 between 1 and 10","select c1,c2,c3,c4,c5 from stb1 where c1 between 1 and 10")
self.check_sample("select sample( c1 ,3 ),t1 from stb1 where c1 between 1 and 10","select c1,t1 from stb1 where c1 between 1 and 10")
# join
tdSql.query("select sample( ct4.c1 , 1 ) from ct1, ct4 where ct4.ts=ct1.ts")