How Can I Efficiently Aggregate a Single Column in Complex SQL Queries?

Aggregate Single Column in Complex Queries

When working with queries containing numerous columns, it can be challenging to aggregate a single column effectively. While the conventional method of including all fields in the SELECT, GROUP BY, and ORDER BY clauses may suffice, it can lead to verbose queries.

Simpler Alternative for PostgreSQL 9.1

If you're using PostgreSQL 9.1 or later, a simpler approach exists. Since you've specified foo1 as the primary key, you can simplify your query as follows:

Aggregate First, Join Later for Multi-Table Queries

However, when dealing with multiple tables and more complex relationships, it may be more efficient to aggregate first and join later. Consider this revised query:

By aggregating and joining separately, you avoid unnecessary aggregation overhead for most of your query.

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