Conditional Aggregation for Inner Joining Multiple SUM/Group Queries with Different WHERE Clauses

The problem at hand involves joining multiple SUM and GROUP queries each with different WHERE clauses using a UNION operator. The objective is to obtain a single record per column, where the columns are independent of each other but joined on a common identifier.

Introduction

Conditional aggregation is a powerful SQL feature that allows us to handle complex calculations involving conditions. In this article, we will explore how to use conditional aggregation to achieve the desired result.

Understanding Conditional Aggregation

Conditional aggregation involves using a function (usually IIF) within the SUM() or AGGREGATE() function to evaluate a condition. If the condition is true, the value associated with that row is included in the sum; if the condition is false, it is ignored.

The Problem at Hand

We have five queries:

1. SUM([Area (Gross Acres)]) AS [Sum(Gross Acres)]
2. SUM([Area (Gross Acres)]) AS [Sum(TX DEL Acres)], with a condition for [COUNTY/PARISH].
3. SUM([Area (Gross Acres)]) AS [Sum(N MID Acres)], with a condition for [COUNTY/PARISH].
4. SUM([Area (Gross Acres)]) AS [Sum(NM DEL Acres)], with a condition for [COUNTY/PARISH].
5. SUM([Area (Gross Acres)]) AS [Sum(S MID Acres)], with a condition for [COUNTY/PARISH].

We need to join these queries on the [Operator Company Name] column using UNION.

The Solution

To solve this problem, we can use conditional aggregation as described in the question. We will create a single query that uses IIF statements within each SUM() function to evaluate the conditions from the original subqueries. If the condition is met, the value is included in the sum; if not, it is ignored.

The Query

Here is the query:

SELECT 
    [Operator Company Name],
    Sum([Area (Gross Acres)]) AS [Sum(Gross Acres)],
    Sum(
        IIF( 
            (
                [COUNTY/PARISH] Like '*Reeves*' 
                OR [COUNTY/PARISH] Like '*Culberson*' 
                OR [COUNTY/PARISH] Like '*Pecos*' 
                OR [COUNTY/PARISH] Like '*Loving*' 
                OR [COUNTY/PARISH] Like '*Ward*' 
                OR [COUNTY/PARISH] Like '*Winkler*'
            ), 
            [Area (Gross Acres)],
            0
        )
    ) AS [Sum(TX DEL Acres)],
    Sum(
        IIF(
            (
                [COUNTY/PARISH] Like '*Dawson*' 
                OR [COUNTY/PARISH] Like '*Borden*' 
                OR [COUNTY/PARISH] Like '*Martin*' 
                OR [COUNTY/PARISH] Like '*Howard*'
            ),
            [Area (Gross Acres)],
            0
        )
    ) AS [Sum(N MID Acres)],
    Sum(
        IIF(
            (
                [COUNTY/PARISH] Like '*Eddy*' 
                OR [COUNTY/PARISH] Like '*Lea*'
            ),
            [Area (Gross Acres)],
            0
        )
    ) AS [Sum(NM DEL Acres)],
    Sum(
        IIF(
            (
                [COUNTY/PARISH] Like '*Midland*' 
                OR [COUNTY/PARISH] Like '*Glasscock*' 
                OR [COUNTY/PARISH] Like '*Upton*' 
                OR [COUNTY/PARISH] Like '*Reagan*'
            ),
            [Area (Gross Acres)],
            0
        )
    ) AS [Sum(S MID Acres)]
FROM Enervus_PrivateData
WHERE [US Region] Like 'Permian'
GROUP BY [Operator Company Name];

Conclusion

Conditional aggregation is a powerful feature in SQL that allows us to handle complex calculations involving conditions. By using IIF statements within the SUM() function, we can join multiple queries on different columns and obtain the desired result.

Note: The exact syntax may vary depending on the database management system you are using.

Last modified on 2025-04-28