使用SQL聚合多个列上的正值

Question

I am trying to do aggregation functions on a specific database table with multiple columns. For example:

Sample Table ID Column1 Column2 Column3 1 3 5 -2 2 -1 4 6 3 2 -1 3

In this example, if I would like to sum the values in the 3 columns, I want to get the following result:
Column1: (3+2)=5, Column2(5+4)=9 and Column3(6+3)=9.
Thus, my question is whether this is possible with a single SQL query or I would have to go through creating temporary tables?

Note: The data set is big.

Answer 1

If I understand correctly, you only want to SUM the positive values, and ignore the negatives? If so try:

SELECT 
    SUM(CASE WHEN Column1 > 0 THEN Column1 ELSE 0 END) AS 'Column1PosTotal',
    SUM(CASE WHEN Column2 > 0 THEN Column2 ELSE 0 END) AS 'Column2PosTotal',
    SUM(CASE WHEN Column3 > 0 THEN Column3 ELSE 0 END) AS 'Column3PosTotal'
FROM Table