SQLAlchemy MySQL IF Statement - sqlalchemy

Question

I'm in the middle of converting an old legacy PHP system to Flask + SQLAlchemy and was wondering how I would construct the following:
I have a model:
class Invoice(db.Model):
paidtodate = db.Column(DECIMAL(10,2))
fullinvoiceamount = db.Column(DECIMAL(10,2))
invoiceamount = db.Column(DECIMAL(10,2))
invoicetype = db.Column(db.String(10))
acis_cost = db.Column(DECIMAL(10,2))
The query I need to run is:
SELECT COUNT(*) AS the_count, sum(if(paidtodate>0,paidtodate,if(invoicetype='CPCN' or invoicetype='CPON' or invoicetype='CBCN' or invoicetype='CBON' or invoicetype='CPUB' or invoicetype='CPGU' or invoicetype='CPSO',invoiceamount,
fullinvoiceamount))) AS amount,
SUM(acis_cost) AS cost, (SUM(if(paidtodate>0,paidtodate,invoiceamount))-SUM(acis_cost)) AS profit FROM tblclientinvoices
Is there an SQLAlchemyish way to construct this query? - I've tried googling for Mysql IF statments with SQlAlchemy but drew blanks.
Many thanks!

Answer 1

Use func(documentation) to generate SQL function expression:
qry = select([
func.count().label("the_count"),
func.sum(func.IF(
Invoice.paidtodate>0,
Invoice.paidtodate,
# #note: I prefer using IN instead of multiple OR statements
func.IF(Invoice.invoicetype.in_(
("CPCN", "CPON", "CBCN", "CBON", "CPUB", "CPGU", "CPSO",)
),
Invoice.invoiceamount,
Invoice.fullinvoiceamount)
)
).label("amount"),
func.sum(Invoice.acis_cost).label("Cost"),
(func.sum(func.IF(
Invoice.paidtodate>0,
Invoice.paidtodate,
Invoice.invoiceamount
))
- func.sum(Invoice.acis_cost)
).label("Profit"),
],
)
rows = session.query(qry).all()
for row in rows:
print row