パラメータ化されたクエリを作成し、Pythonを関数にカプセル化する任意の方法

名前付き引数をcursor.execute()に渡したい場合 、%(name)sを使用できます 構文とdictを渡します。 ドキュメント を参照してください。 詳細については。

クエリを使用した例を次に示します。

import datetime
import psycopg2

EXAMPLE_QUERY = """
SELECT
    date_trunc('week', date_received) AS received_week,
    cl_val,
    ROUND(ROUND(SUM(quant_received * standard_price)::numeric,4) / SUM(quant_received),4) AS mk_price_1,
    ROUND(ROUND(SUM(quant_received * mg_fb_price)::numeric,4) / SUM(quant_received),4) AS mg_price_1,
    ROUND(ROUND(SUM(quant_received * mk_price_variance)::numeric,4) / SUM(quant_received),4) AS fb_mk_price_var,
    ROUND(ROUND(SUM(quant_received * freight)::numeric,4) / SUM(quant_received),4) AS freight_new,
    ROUND(ROUND(SUM(quant_received * grd_delv_cost)::numeric,4) / SUM(quant_received),4) AS grd_delv_cost_new,
    TO_CHAR(SUM(quant_received), '999G999G990D') AS Volume_Received
FROM mytable
WHERE date_received >= %(min_date_received)s
    AND date_received <= %(max_date_received)s
    AND item_type = %(item_type)s
    AND cl_val IN %(cl_vals)s
    AND order_type IN %(order_types)s
    AND pk_name IN %(pk_names)s
    AND pk_est NOT IN %(pk_ests)s
GROUP BY received_week ,cl_val
ORDER BY received_week ASC, cl_val ASC;
"""


def execute_example_query(cursor, **kwargs):
    """Execute the example query with given parameters."""
    cursor.execute(EXAMPLE_QUERY, kwargs)
    return cursor.fetchall()
            

if __name__ == '__main__':
    connection = psycopg2.connect(database="myDB", user="postgres", password="passw", host="localhost", port=5432)
    cursor = connection.cursor()
    execute_example_query(
        cursor,
        min_date_received = datetime.date(2010, 10, 1),
        max_date_received = datetime.date(2012, 12, 31),
        item_type = 'processed',
        cl_vals = ('12.5', '6.5', '8.1', '8.5', '9.0'),
        order_types = ('formula',),
        pk_names = ('target', 'costco', 'AFG', 'KFC'),
        pk_ests = ('12',)
    )