Great! There is an alternative CTE syntax, where we define the columns explicitly:
WITH some_name (cte_columns) AS ( your_cte )
In other words, we now have two pairs of parentheses. First, we provide the names of the columns that our CTE will have. Second, we define the actual CTE, based on the columns we provided.
WITH project_revenue (id, sum_amount) AS (
ON donation.project_id = project.id
GROUP BY project.id
The column definition is not required. Why would we use it? It increases the readability of your query. Also, while simple columns inside CTEs don't require aliases, aggregates and other function results do. Columns like
COUNT(project_id) must be given names so that you can refer to them outside the CTE. One way to do this is to use the keyword
AS, just as we did previously. Another way is to provide a list of columns. Either method is fine, but if you use neither, an error will occur.