SQL Server 2019

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CREATE TABLE mytable(
   number INTEGER  NOT NULL PRIMARY KEY 
  ,grade  INTEGER  NOT NULL
  ,weight INTEGER  NOT NULL
);
INSERT INTO mytable(number,grade,weight) VALUES (1,1,185);
INSERT INTO mytable(number,grade,weight) VALUES (2,1,179);
INSERT INTO mytable(number,grade,weight) VALUES (3,3,191);
INSERT INTO mytable(number,grade,weight) VALUES (4,3,192);
INSERT INTO mytable(number,grade,weight) VALUES (5,3,193);
INSERT INTO mytable(number,grade,weight) VALUES (6,1,194);
INSERT INTO mytable(number,grade,weight) VALUES (7,1,196);
INSERT INTO mytable(number,grade,weight) VALUES (8,1,188);
INSERT INTO mytable(number,grade,weight) VALUES (9,1,187);
INSERT INTO mytable(number,grade,weight) VALUES (10,1,200);
INSERT INTO mytable(number,grade,weight) VALUES (11,2,201);
INSERT INTO mytable(number,grade,weight) VALUES (12,2,202);
INSERT INTO mytable(number,grade,weight) VALUES (13,2,203);
INSERT INTO mytable(number,grade,weight) VALUES (14,2,191);
INSERT INTO mytable(number,grade,weight) VALUES (15,2,187);

15 rows affected

number	grade	weight
1-2	1	364
3-5	3	576
6-10	1	965
11-15	2	984