How to merge duplicate records in a database table, while summing one of the table fields?

Question

SQL Server

You need to merge records with the same Pole_Id, Month, Year into one record, while adding their Count fields.

Answer 1

Since you haven't specified what to do with ID, you can make a grouping request. Add its result to a copy of the table and swap them. Or filter the grouping result by the number of records COUNT(*) > 1, delete by Pole_Idand add amounts.

SELECT Pole_id, Month, Year, SUM(Count)
 FROM [Table]
 GROUP BY Pole_id, Month, Year
 HAVING (COUNT(*) > 1)