➕ Sum or Max of Multiple Columns

Configurable Joins makes it easy to use the aggregate SQL functions like SUM() or MAX(). However, these operate across rows - what you want the max or sum of several columns on the same row? 🚣‍♀️

Example of trying and failing to use Maximum on multiple exports:

Solution: Table value constructors make it easy to apply aggregate functions across columns. Example use cases:

• Select the latest of three or more dates from different bases
• Select the minimum of three or more dates
• Compute the average of multiple exports

This article lists two examples, but any aggregate function will work.

Max

A table value constructor can also return the maximum non-null value from a set:

(SELECT MAX(v)
FROM (
    VALUES (@value1)
        ,(@value2)
    ) AS t(v))

However, there’s an easier way: the GREATEST() function! It does essentially the same thing with less fuss.

GREATEST(@value1, @value2)

Sum

Easily sum all non-null values from a set. Replace @valueX with your whatever exports you desire.

(SELECT SUM(v)
FROM (
    VALUES (@value1)
        ,(@value2)
    ) AS t(v))

Occasionally, you may encounter datatype errors when all values are NULL and have datatypes incompatible with SUM(). Adding the following extra “value” should prevent this.
,(cast(NULL AS INT)) /* Prevent datatype error */