Read SQL into dataframe

The key line is:

pd.read_sql(query.statement, db.engine, index_col="date")

read_sql() docs

Things I learnt

Needs db engine. Using Flask SQLAlchemy you can access the engine with

db.engine

Expects a SQL string. Not how do things in FlaskSQLAlchemy, don't write your own SQL, compose queries. E.g.

PriceData.query.filter_by(symbol="AAPL", interval="day").filter(
        PriceData.date.between("2021-03-01", "2021-04-08")

But you can get the SQL by tacking statement on the end of the query object. E.g.

sql = PriceData.query.filter_by(symbol="AAPL", interval="day").filter(
        PriceData.date.between("2021-03-01", "2021-04-08").statement

or

query = PriceData.query.filter_by(symbol="AAPL", interval="day").filter(
        PriceData.date.between("2021-03-01", "2021-04-08")
sql = query.statement