小编pha*_*don的帖子

我有这样的表:

Person    City    workingdate
A    Newyork    10.11.2015
A    Newyork    11.11.2015
A    Newyork    12.11.2015
B    Newyork    10.11.2015
B    Newyork    15.11.2015
B    Newyork    16.11.2015
B    Newyork    18.11.2015

我想要一个列出城市内不同人物的专栏:

Person    City    workingdate  countdistinctpersonincity
A    Newyork    10.11.2015             1
A    Newyork    11.11.2015             0
A    Newyork    12.11.2015             0
B    Newyork    10.11.2015             1
B    Newyork    15.11.2015             0
B    Newyork    16.11.2015             0
B    Newyork    18.11.2015             0

你能帮帮我怎么做吗？

CREATE TABLE Persons
(Person varchar(25),
City varchar(255),
workingdate varchar(10));

insert into Persons
values ('A', 'Newyork','10.11.2015'),
('A', 'Newyork','11.11.2015'),
('A', 'Newyork','12.11.2015'),
('B', 'Newyork','10.11.2015'), …

我有一列包含这样的数据“08.06.2017/10:20:46”。数据类型为字符串。我想将其转换为时间戳。我尝试了 CAST("08.06.2017/10:20:46" AS TIMESTAMP) 但它不起作用你能帮我转换它吗？谢谢