Inline SQL
A simple embedded language for running inline SQL in Python programs.
from inline_sql import sql, sql_val
assert sql_val^ "SELECT 1 + 1" == 2
x = 5
assert sql_val^ "SELECT $x * 2" == 10
df = sql^ "SELECT * FROM (VALUES (1, 10), (2, 20)) df (x, y)"
assert sql_val^ "SELECT SUM(x) + SUM(y) FROM df" == 33Operations in the inline_sql library run directly inside your process. You can query local datasets (pandas frames), CSV files, and even interpolate variables seamlessly. This is implemented as a small wrapper around DuckDB, so it is extremely fast.
Installation
Supports Python 3.7+, tested on all major operating systems.
pip install inline-sqlUsage
The exported sql and sql_val variables are magic objects that can be used to run queries. Queries can read from local dataframes by name, and they can embed parameters using dollar-sign notation.
>>> from inline_sql import sql, sql_val
>>> sql_val^ "SELECT 1 + 1"
2
>>> x = 5
>>> sql_val^ "SELECT 2 * $x"
10
>>> sql^ "SELECT * FROM 'disasters.csv' LIMIT 5"
Entity Year Deaths
0 All natural disasters 1900 1267360
1 All natural disasters 1901 200018
2 All natural disasters 1902 46037
3 All natural disasters 1903 6506
4 All natural disasters 1905 22758
>>> disasters = sql^ "SELECT * FROM 'disasters.csv'"
>>> def total_deaths(entity: str) -> float:
... return sql_val^ "SELECT SUM(deaths) FROM disasters WHERE Entity = $entity"
...
>>> total_deaths("Drought")
11731294.0
>>> total_deaths("Earthquake")
2576801.0You can run any SQL query as described in the DuckDB documentation.
Library Use
You can use inline_sql as a library. Since results from queries are ordinary pandas.DataFrame objects, they work in functions and application code. Here's a longer example:
import pandas as pd
from inline_sql import sql, sql_val
def head_data(count: int) -> pd.DataFrame:
return sql^ "SELECT * FROM 'cars.csv' LIMIT $count"
cars = head_data(50)
origin_counts = sql^ """
SELECT origin, COUNT() FROM cars
GROUP BY origin
ORDER BY count DESC
"""
print(origin_counts)
most_common = origin_counts.origin[0]
print(sql_val^ """
SELECT AVG(horsepower) FROM cars
WHERE origin = $most_common
""")In general, sql_val is used to run scalar queries, while sql is used to run queries that return tables.
Acknowledgements
Created by Eric Zhang (@ekzhang1). Licensed under the MIT license.