python - 如何使用 argparse Python 在 SQL 查询中传递日期范围参数

Question

我有 3 个参数日期、名称和国家/地区，此代码允许为我的 SQL 查询传递我的可选参数，例如：

import argparse
parser = argparse.ArgumentParser()

# provide a clear definition of possible arguments
parser.add_argument('--date', type=str, required=False, default=None)
parser.add_argument('--Name', type=str, required=False, default=None)
parser.add_argument('--country', type=str, required=False, default=None)

# get arguments passed in
args = parser.parse_args()

args = args.__dict__

# form statement based on arguments that were given
columns = ' and '.join([x+'=%s' for x in args if args[x]])     #check that args[x] is not None

vars = tuple([args[x] for x in args if args[x]])

statement = "SELECT * FROM TABLE WHERE "+columns

cursor.execute(statement, vars)

我的 SQL 查询：

'SELECT * FROM TABLE WHERE date=%s and name=%s'

我想调用我的脚本：

script.py --date=var1 --name=var3

现在，如果我有一个日期范围，我如何between在我的 SQL 中添加这个参数和关闭来进行如下查询：

'SELECT * FROM TABLE WHERE date between %s and %s and name=%s'

请问我该怎么做

标签： pythonpostgresqlargumentsargparse

Answer 1

我想这就是你要找的：

import argparse

parser = argparse.ArgumentParser()
parser.add_argument("--date", nargs=2)
parser.add_argument("--name")
parser.add_argument("--country")

# Use `vars` to get a dict of arguments
args = vars(parser.parse_args())
# Only keep arguments that aren't `None`
args = {k: v for k, v in args.items() if v is not None}

# Base select statement
statement = "SELECT * FROM TABLE"

# This list will hold all the extra conditionals
operators = []

if "date" in args:
    # Specifically parse the dates and then delete it from args
    operators.append("date BETWEEN {} AND {}".format(*args["date"]))
    del args["date"]

# For the remaining args add them to operators
for k, v in args.items():
    operators.append("{}={}".format(k, v))

if operators:
    # If there are extra operators add them to the base statement
    statement = statement + " WHERE " + " and ".join(operators)
print(statement)

我在这里做了什么：

• 使用指定--date参数的数量nargs=2
• 用于vars获取字典而不是args.__dict__
• 添加了一个特殊的检查date
• 使用 for 循环添加其他可选参数

您可以在下面看到一些示例输出：

python3 script.py --date 2020-08-01 2020-12-25 --name alex --country Canada
SELECT * FROM TABLE WHERE date BETWEEN 2020-08-01 AND 2020-12-25 and name=alex and country=Canada

python3 script.py --date 2020-08-01 2020-12-25 --name alex
SELECT * FROM TABLE WHERE date BETWEEN 2020-08-01 AND 2020-12-25 and name=alex

python3 script.py --name alex
SELECT * FROM TABLE WHERE name=alex

python3 script.py
SELECT * FROM TABLE