MySQL:Jumlahkan nilai dalam subkueri

Beberapa saran:

• Bergabung di seasons sekali. Gabung menyebabkan baris dari tabel kiri diduplikasi, sehingga dapat dijumlahkan dua kali dengan sum agregat. Jika ragu, jalankan kueri tanpa group by untuk contoh sekolah.
• Anda harus menghubungkan subquery ke outer query dengan sesuatu seperti inner_schools.id = outer_schools.id
• Tapi sejauh yang saya lihat, Anda tidak memerlukan subquery sama sekali

Misalnya:

SELECT  schools.*
,       sum(cashflows.amount) total_branding_cashflow
FROM    schools
JOIN    seasons
ON      seasons.school_id = schools.id 
        and seasons.year = 2010
JOIN    cashflows
ON      cashflows.season_id = seasons.id 
        and cashflow_group_id = 12
GROUP BY 
        schools.id 
HAVING  total_branding_cashflow BETWEEN 50000000 AND 100000000

Untuk beberapa kategori, Anda dapat menggunakan kasus:

SELECT  schools.*
,       sum(case when cashflow_group_id = 1 then cashflows.amount end) total1
,       sum(case when cashflow_group_id = 12 then cashflows.amount end) total12
FROM    schools
JOIN    seasons
ON      seasons.school_id = schools.id 
        and seasons.year = 2010
JOIN    cashflows
ON      cashflows.season_id = seasons.id 
GROUP BY 
        schools.id