Aggregation Queries - sqlite

Question

Is it possible to do the following query in SQLite.Swift without resorting to arbitrary SQL (which I do have working but would prefer to avoid)?
select table1.id, sum(table1.col1*table2.col2)
from table1, table2
where table1.id=table2.id
group by table1.id
I've attempted the following: the SQL (through asSQL()) appears to be correct, but I can't find a way to reference the aggregate column from the returned row.
let query = table1.select(id, (table1[column1]*table2[column2]).sum
.join(table2, on: table1[id] == table2[id])
.group(id)
Can you alias columns somehow?

Answer 1

OK, I've found the solution, and it only took me 2 days!
The way to alias a column in SQLite.swift is to use an expression.
The name of the expression becomes the column alias.
So instead of
let query = table1.select(id, (table1[column1]*table2[column2]).sum)
.join(table2, on: table1[id] == table2[id])
.group(id)
Use:
let aggrColumn = (table1[column1]*table2[column2]).sum
let query = table1.select(id, aggrColumn)
.join(table2, on: table1[id] == table2[id])
.group(id)
let results = try db.prepare(query)
for row in results {
myAggrColumn = try row.get(aggrColumn)
}

Answer 2

Using
select id, sum(table1.col1*table2.col2)
from table1, table2
were table1.id=table2.id
group by id
Will result (see below for corrections) in 2 columns, namely id and sum(table1,col*table2.col2)
However both uses of id would be ambiguous as coded as there are two such source columns.
As such the query should be changed (see following code whihc assumes you want the id from table1 (shouldn't matter if table2 were used due to the join))
Additionally were is not a keyword, it should be WHERE
An alias would likely make things easier you make an alias using the AS keyword. The folloiwng also includes AS mysumcolumn thus the resultant columns will be id and mysumcolumn
select table1.id, sum(table1.col1*table2.col2) AS mysumcolumn
from table1, table2
where table1.id=table2.id
group by table1.id
Running this with no data results in :-