根据多个列按日期时间获取最新记录

如何解决根据多个列按日期时间获取最新记录

想知道如何在postgresql中做些什么，我有一张桌子，

AcctNo    EntryDate        EntryTime   Form    FormSeq   anscode   answer
123456    8/14/20           07:05      ORREC    0001      ans1      1245
123456    8/13/20           07:07      ORREC    0001      ans1      1235
123456    8/14/20           07:04      ORREC    0001      ans2      test
123456    8/14/20           07:05      ORREC    0001      ans2      testing
123456    8/15/20           12:15      ORREC    0002      ans1      1520
123456    8/15/20           12:17      ORREC    0002      ans1      1522

我需要根据日期和时间获取每个form / formseq / anscode的最后一个条目

所以我得到的三个结果是

AcctNo    EntryDate       EntryTime   Form    FormSeq   anscode   answer
123456    8/14/20          07:05      ORREC    0001      ans1      1245
123456    8/14/20          07:05      ORREC    0001      ans2      testing
123456    8/15/20          12:17      ORREC    0002      ans1      1522

select AcctNo,EntryDate,EntryTime,Form,FormSeq,anscode,answer 
from TableName 
where       
Group By AcctNo,Anscode

解决方法

下面是一个完整的示例。它与您的数据输出不完全匹配。但这确实与“根据日期和时间获取每个表单/ formseq / anscode的最后一个条目”相匹配。因此，它将返回每个日期的最后一个条目。如果您希望每个表单/ formseq / anscode的最后输入期是一个不同的查询。

CREATE TABLE public.test_table (
    acctno integer,entrydate date,entrytime time without time zone,form character varying,formseq character varying,anscode character varying,answer character varying
);

COPY public.test_table (acctno,entrydate,entrytime,form,formseq,anscode,answer) FROM stdin;
123456  2020-08-14      07:05:00        ORREC   0001    ans1    1245
123456  2020-08-13      07:07:00        ORREC   0001    ans1    1235
123456  2020-08-14      07:04:00        ORREC   0001    ans2    test
123456  2020-08-14      07:05:00        ORREC   0001    ans2    testing
123456  2020-08-15      12:15:00        ORREC   0002    ans1    1520
123456  2020-08-15      12:17:00        ORREC   0002    ans1    1522
\.

SELECT
     distinct on(entrydate,formSeq,anscode)  acctno,answer
from
    test_table
WHERE
   acctNo = 123456
ORDER BY
     entrydate,entrytime desc;

 acctno | entrydate  | entrytime | form  | formseq | anscode | answer  
--------+------------+-----------+-------+---------+---------+---------
 123456 | 2020-08-13 | 07:07:00  | ORREC | 0001    | ans1    | 1235
 123456 | 2020-08-14 | 07:05:00  | ORREC | 0001    | ans1    | 1245
 123456 | 2020-08-14 | 07:05:00  | ORREC | 0001    | ans2    | testing
 123456 | 2020-08-15 | 12:17:00  | ORREC | 0002    | ans1    | 1522

第二个查询，其输出类似于您的数据示例：

SELECT DISTINCT ON (form,anscode)
    acctno,answer
FROM
    test_table
ORDER BY
    form,entrydate + entrytime DESC;

acctno | entrydate  | entrytime | form  | formseq | anscode | answer  
--------+------------+-----------+-------+---------+---------+---------
 123456 | 2020-08-14 | 07:05:00  | ORREC | 0001    | ans1    | 1245
 123456 | 2020-08-14 | 07:05:00  | ORREC | 0001    | ans2    | testing
 123456 | 2020-08-15 | 12:17:00  | ORREC | 0002    | ans1    | 1522