改进 SCD2 解决方案的插入查询

Question

I have two insert statements. The first query is to inserta new row if the id doesn't exist in the target table. The second query inserts to the target table only if the joined id hash value is different (indicates that the row has been updated in the source table) and the id in the source table is not null. These solutions are meant to be used for my SCD2 solution, which will be used for inserts of hundreds thousands of rows. I'm trying not to use the MERGE statement for practices.

The columns "Current" value 1 indicates that the row is new and 0 indicates that the row has expired. I use this information later to expire my rows in the target table with my update queries.

Besides indexing is there a more competent and effective way to improve my insert queries in a way that resembles the like of the SCD2 merge statement for inserting new/updated rows?

Query:

Query 1:
INSERT INTO TARGET
SELECT Name,Middlename,Age, 1 as current,Row_HashValue,id
from Source s
Where s.id not in (select id from TARGET) and s.id is not null

Query 2:
INSERT INTO TARGET
SELECT Name,Middlename,Age,1 as current ,Row_HashValue,id
FROM SOURCE s 
LEFT JOIN TARGET t ON s.id = t.id
AND s.Row_HashValue = t.Row_HashValue
WHERE t.Row_HashValue IS NULL and s.ID IS NOT NULL

Answer 1

You can use WHERE NOT EXISTS , and have just one INSERT statement:

INSERT INTO TARGET
SELECT Name,Middlename,Age,1 as current ,Row_HashValue,id
FROM SOURCE s 
WHERE NOT EXISTS (
    SELECT 1
    FROM TARGET t 
    WHERE s.id = t.id
    AND s.Row_HashValue = t.Row_HashValue)
AND s.ID IS NOT NULL;