SQL Server 2017

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CREATE TABLE SourceTable 
    ([COL1] int, [COL2] varchar(1), [COL3] varchar(5), [VALUE] int, [DATE] datetime)
;

CREATE TABLE TargetTable  
    ([COL1] int, [COL2] varchar(1), [COL3] varchar(5), [VALUE] int, [DATE] datetime)
;
    
INSERT INTO SourceTable 
    ([COL1], [COL2], [COL3], [VALUE], [DATE])
VALUES
    (1, 'A', 'TYPE', 3, '2019-01-02 00:00:00'),
    (2, 'B', 'KIND', 4, '2019-01-03 00:00:00'),
    (1, 'A', 'COLOR', 0, '2019-01-02 00:00:00'),
    (2, 'B', 'KIND', 0, '2019-01-03 00:00:00')
;


4 rows affected

MERGE TargetTable T
    USING SourceTable s  
       ON (                   
                 S.COL1  = T.COL1
             AND S.COL2  = T.COL2
             AND S.COL3  = T.COL3
             AND S.DATE  = T.DATE                                    
          )
    WHEN MATCHED AND
        (                   
            ISNULL(S.VALUE,'')  <> ISNULL(T.VALUE,'')
        )
    THEN UPDATE
     SET T.VALUE  = S.VALUE                          
     
    WHEN NOT MATCHED
    THEN INSERT VALUES
        (                   
             S.COL1 
            ,S.COL2 
            ,S.COL3
            ,S.VALUE    
            ,S.DATE
        );
        
4 rows affected

SELECT * FROM TargetTable;


COL1
COL2
COL3
VALUE
DATE


1
A
TYPE
3
2020-01-10 09:45:32

2
B
KIND
4
2020-01-10 09:45:32

1
A
COLOR
0
2020-01-10 09:45:32

2
B
KIND
0
2020-01-10 09:45:32


MERGE TargetTable T
    USING SourceTable s  
       ON (                   
                 S.COL1  = T.COL1
             AND S.COL2  = T.COL2
             AND S.COL3  = T.COL3
             AND S.DATE  = T.DATE                                    
          )
    WHEN MATCHED AND
        (                   
            ISNULL(S.VALUE,'')  <> ISNULL(T.VALUE,'')
        )
    THEN UPDATE
     SET T.VALUE  = S.VALUE + 10
     
    WHEN NOT MATCHED
    THEN INSERT VALUES
        (                   
             S.COL1 
            ,S.COL2 
            ,S.COL3
            ,S.VALUE    
            ,S.DATE
        );
        
2 rows affected

SELECT * FROM TargetTable;


COL1
COL2
COL3
VALUE
DATE


1
A
TYPE
3
2020-01-10 09:45:32

2
B
KIND
10
2020-01-10 09:45:32

1
A
COLOR
0
2020-01-10 09:45:32

2
B
KIND
14
2020-01-10 09:45:32
COL1	COL2	COL3	VALUE	DATE
1	A	TYPE	3	2020-01-10 09:45:32
2	B	KIND	4	2020-01-10 09:45:32
1	A	COLOR	0	2020-01-10 09:45:32
2	B	KIND	0	2020-01-10 09:45:32