Return single string from pypyodbc database query

Question

I'm trying to pull a single value back from a MSSQL DB, the code looks like:

import pandas as pd
import pypyodbc
query = 'SELECT TOP(1) value FROM [dbo].[table]'
connection = pypyodbc.connect(...)
df = pd.read_sql_query(query, connection)

But this returns a dataframe object, is there a method to instead just return a single string value, possibly without Pandas. Key priority being speed. Is there a quicker way generally of connecting/querying?

Answer 1

Consider implementing your algorithm in a vectorized Pandas/NumPy/SciPy/SKLearn way if processing speed is important for you.

Using vectorized approach usually means using internal functions that are working with vectors and matrices instead of scalars and that are implemented with C, C-Python, etc. (optimized) instead of writing loops.

If your algorithm can't be vectorized you still can speed up your algorithm - read all the data you want to process at once instead of doing it in a loop:

query = 'SELECT value FROM [dbo].[table]'  # <-- NOTE: i have intentionally removed `TOP(1)`
connection = pypyodbc.connect(...)
df = pd.read_sql_query(query, connection)

# process your data (from the DataFrame) here...