Access SQL Group by with condition - sql

Question

I'm using MS Access for the following task (due to office restrictions). I'm quite new to SQL.
I have the following table:
I want to select all stores grouped by street, zip and place. But i only want to group them, if the SquareSum (after Group by) is < 1000. Rue de gare 2 should be grouped, while Bahnhofstrasse 23 should be seperate lines.
So far as i know MS Access doesn't allow a case statement. So my query looks like this:
SELECT
Street,
ZIP,
Place,
Sum(Square) AS SumSquare,
FROM Table1
SWITCH (SumSquare > 1000, GROUP BY (Street, ZIP, Place))
I also tried:
GROUP BY
SWITCH (SumSquare > 1000, (Street, ZIP, Place))
But it keeps telling me i have a syntax error. Could someone please help me?

Answer 1

In Access, I would do this with several queries.
This would be easier to do if you had an id on the rows (such as an autonumber).
First query identifies the streets that should be summed.
query: SumTheseStreets
SELECT
Street,
ZIP,
Place,
Sum(Square) AS SumSquare
FROM Table1
GROUP BY Street, ZIP, Place
HAVING sum(Square) < 1000
Note the HAVING which is a bit like a WHERE clause that's applied outside of the GROUP BY or SUM
Second query identifies the other rows (notes on this one below):
query: StreetsNotSummed
SELECT
Street,
ZIP,
Place,
Square AS SumSquare
FROM Table1
LEFT JOIN SumTheseStreets ON Table1.Street = SumTheseStreets.Street AND Table1.ZIP = SUmTheseStreets.ZIP AND Table1.Place = SumTheseStreets.Place
WHERE SumTheseStreets.Street IS NULL;
A couple of notes:
I've called the field SumSquare because I want it to be the same name as the SumSquare field in the first query
It uses the first query as one of the input "tables"
This uses a LEFT JOIN which means "give me all of the rows in the first table (table1) and if any rows in the second table (SumTheseStreets) match, put those in as well.
but then it filters out the rows that DO match.
So this query only lists the streets that you want NOT summed.
So now you need a third query.
This simply includes all of the rows in both of those queries.
I'm not too sure on the Access syntax on this one, but there's a union query wizard if this isn't right.
Query: TheAnswerRequired
SELECT
Street,
ZIP,
Place,
SumSquare
FROM SumTheseStreets
UNION
SELECT
Street,
ZIP,
Place,
SumSquare
FROM StreetsNotSummed
(it might need to be UNION ALL)
Good luck.

Answer 2

You can use UNION ALL:
SELECT ts.*
FROM (SELECT Street, Zip, Place, SUM(Square) as SumSquare
FROM Table1
GROUP BY Street, Zip, Place
) as ts
WHERE ts.SumSquare < 1000
UNION ALL
SELECT t1.*
FROM Table1 as t1 INNER JOIN
(SELECT Street, Zip, Place, SUM(Square) as SumSquare
FROM Table1
GROUP BY Street, Zip, Place
) as ts
ON t1.Street = ts.Street AND t1.Zip = ts.Zip and t1.Place = ts.Place
WHERE ts.SumSquare >= 1000