How to SUM two fields within an SQL query

I need to get the total of two fields which are within the same row and input that number in a field at the end of that same row.

This is my code.

Sum(tbl1.fld1 + tbl1.fld2) AS [Total]

Is this what the SUM function is used for, or can you only use the SUM function for getting the total of a column?

Thanks

Answer

SUM is an aggregate function. It will calculate the total for each group. + is used for calculating two or more columns in a row.

Consider this example,

ID  VALUE1  VALUE2
===================
1   1       2
1   2       2
2   3       4
2   4       5

 

SELECT  ID, SUM(VALUE1), SUM(VALUE2)
FROM    tableName
GROUP   BY ID

will result

ID, SUM(VALUE1), SUM(VALUE2)
1   3           4
2   7           9

 

SELECT  ID, VALUE1 + VALUE2
FROM    TableName

will result

ID, VALUE1 + VALUE2
1   3
1   4
2   7
2   9

 

SELECT  ID, SUM(VALUE1 + VALUE2)
FROM    tableName
GROUP   BY ID

will result

ID, SUM(VALUE1 + VALUE2)
1   7
2   16