Question

我试图在Redshift中将Netezza AGE功能实现为UDF。我可以在Python（Spyder IDE-Py 3.6）中获得正确的答案，但是当我在Redshift中将其作为UDF执行时，会给我错误的输出。

我尝试在Redshift中以select AGE_UDF('1994-04-04 20:10:52','2018-09-24 11:31:05');的身份执行。这是RS UDF中使用的代码。

CREATE OR REPLACE FUNCTION AGE_UDF (START_DATE TIMESTAMP, END_DATE TIMESTAMP)
    RETURNS varchar(100)
stable
AS $$
    from datetime import datetime
    from dateutil import relativedelta

    START_DATE = datetime.strptime(START_DATE, '%Y-%m-%d %H:%M:%S')

    END_DATE = datetime.strptime(END_DATE, '%Y-%m-%d %H:%M:%S')

    difference = relativedelta.relativedelta(END_DATE, START_DATE)

    years = difference.years
    months = difference.months
    days = difference.days
    hours = difference.hours
    minutes = difference.minutes
    seconds = difference.seconds
    age=''
    if years == 0: 
        age='' 
    elif years == 1:
        age+=str(years)+' year '
    else:
        age+=str(years)+' years '

    if months == 0: 
        age+='' 
    elif months == 1:
        age+=str(months)+' mon '
    else:
        age+=str(months)+' mons '

    if days == 0: 
        age+='' 
    elif days == 1:
        age+=str(days)+' day '
    else:
        age+=str(days)+' days '

    age+=str(hours)+':'+str(minutes)+':'+str(seconds)
    return age
$$ language plpythonu;

RS中的输出： -8809.15：20：13

这是Python（3.6）中使用的代码。

from datetime import datetime
from dateutil import relativedelta

START_DATE = '1994-04-04 20:10:52'
START_DATE = datetime.strptime(START_DATE, '%Y-%m-%d %H:%M:%S')

END_DATE = '2018-09-24 11:31:05'
END_DATE = datetime.strptime(END_DATE, '%Y-%m-%d %H:%M:%S')

difference = relativedelta.relativedelta(END_DATE, START_DATE)

years = difference.years
months = difference.months
days = difference.days
hours = difference.hours
minutes = difference.minutes
seconds = difference.seconds
age=''
if years == 0: 
    age='' 
elif years == 1:
    age+=str(years)+' year '
else:
    age+=str(years)+' years '


if months == 0: 
    age+='' 
elif months == 1:
    age+=str(months)+' mon '
else:
    age+=str(months)+' mons '


if days == 0: 
    age+='' 
elif days == 1:
    age+=str(days)+' day '
else:
    age+=str(days)+' days '

age+=str(hours)+':'+str(minutes)+':'+str(seconds)
print(age)

Python输出： 24年5个月19天15:20:13

编辑：

我找到了实现Netezza功能的方法，并将其粘贴在这里。 我仍然期待另一种有效的方法！欢呼!!!

感谢支持和建议!!!

Answer 1

不需要Python。这是封装逻辑的SQL UDF。如果单位复数对您很重要（noImplicitAny与mons），则需要扩展它。

mon

Answer 2

我找到了与Netezza相同的输出方式！我们需要用不同的输入创建4个不同的UDF！在这里，我为（TIMESTAMP，TIMESTAMP）添加了UDF

create or replace function AGE_UDF_V2 (START_DATE TIMESTAMP, END_DATE TIMESTAMP)
  returns VARCHAR
stable
as $$
# -*- coding: utf-8 -*-
"""
Created on Wed Sep 26 12:59:24 2018

@author: pnataraj
"""

from dateutil import relativedelta
from dateutil.parser import parse

if (START_DATE is None or END_DATE is None):
    return None

else:
    START_DATE = str(START_DATE).strip()
    END_DATE = str(END_DATE).strip()

    START_DATE = parse(START_DATE)
    END_DATE = parse(END_DATE)

    difference = relativedelta.relativedelta(START_DATE, END_DATE)
    years = difference.years
    months = difference.months
    days = difference.days
    hours = difference.hours
    minutes = difference.minutes
    seconds = difference.seconds
    age=''
    if years != 0:
        if years == 1 or years == -1:
            age+=str(years)+' year '
        else:
            age+=str(years)+' years '

    if months != 0:
        if months == 1 or months == -1:
            age+=str(months)+' mon '
        else:
            age+=str(months)+' mons '

    if days != 0: 
        if days == 1 or days == -1:
            age+=str(days)+' day '
        else:
            age+=str(days)+' days '

    if (hours !=0 or minutes !=0 or seconds != 0):
        if (hours < 0 or minutes < 0 or seconds < 0):
            age+=str("-"+format(abs(hours),"02")+":"+format(abs(minutes),"02")+":"+format(abs(seconds),"02"))
        else:
            age+=str(format(hours,"02")+":"+format(minutes,"02")+":"+format(seconds,"02"))
    elif(hours == 0 and minutes ==0 and seconds == 0):
        if len(age)>0:
            age = age
        else:
            age = "00:00:00"

    return age.strip()
$$ language plpythonu;

感谢所有建议和帮助！希望对正在执行Nz到AWS RS迁移的人有帮助！

Netezza内置AGE在Redshift中用作UDF

2 个答案: