Merge the table based on date and condition

I have following table:

DROP TABLE IF EXISTS t

CREATE TABLE t
(
    id INT IDENTITY PRIMARY KEY,
    dt datetime,
    type int,
    grp int,
    typecol1 varchar(10),
    typecol2 varchar(10),
    typecol3 varchar(10),
    typecol4 varchar(10)
)

INSERT INTO t (dt,type,grp,typecol1,typecol2,typecol3,typecol4) 
VALUES
('2019-01-15',1,1,'A',null,null,null),
('2019-01-15',2,2,null,'B',null,null),
('2019-01-15',3,3,null,null,'C',null),
('2019-01-15',4,4,null,null,null,'D'),
('2019-02-15',1,1,'AA',null,null,null),
('2019-02-15',4,2,null,null,null,'DD'),
('2019-03-15',3,1,null,null,'CCC',null),
('2019-04-15',2,1,null,'BBBB',null,NULL);

In this table type will be 1,2,3,4.. here date and type both are composite key.

I need to merge the row based if same date exist to single row and merge based on only below condition

if same date & 
   type=1 then merge to typecol1
   type=2 then merge to typecol2
   type=3 then merge to typecol3
   type=4 then merge to typecol4

and grp col is based on running count of date.

Answer

Try GROUP BY

FIDDLE DEMO

SELECT dt, MAX(typecol1) typecol1, MAX(typecol2) typecol2, MAX(typecol3) typecol3,
       MAX(typecol4) typecol4
FROM t
GROUP BY dt

Output

dt                  typecol1    typecol2    typecol3    typecol4
15/01/2019 00:00:00 A           B           C           D
15/02/2019 00:00:00 AA                                  DD
15/03/2019 00:00:00                         CCC 
15/04/2019 00:00:00             BBBB