Help in Query for max date

Question

Hi, How I can get the max(Gst_date) record of GRD. IF record of GRD has more than one record then I need the one max(GST_date) record of every GRD. Thanks.
create table #CRT (CRT numeric, GRD numeric, GST_Date datetime)
insert into #CRT values (7 ,1900,'01-01-2000')
insert into #CRT values (19,1900,'01-01-2002')
insert into #CRT values (24,1900,'01-01-2013')
insert into #CRT values (7 ,2100,'01-01-2010')
insert into #CRT values (19,2100,'01-01-2012')
insert into #CRT values (7 ,2200,'01-01-2012')
insert into #CRT values (19,2200,'02-02-2012')
I would like the following output from query. The following record is the max(GST_Date ) of every '''GRD'".
CRT   GRD   GST_Date
24    1900  01-01-2013
19    2100  01-01-2012
19    2200  02-02-2012

Answer 1

Please follow basic Netiquette and post the DDL we need to answer this. Follow industry and ANSI/ISO standards in your data. You should follow ISO-11179 rules for naming data elements. Everything you posted is wrong. You should follow ISO-8601 rules for
displaying temporal data. In fact is is required by ANSI/ISO Standards. You failed again. We need to know the data types, keys and constraints on the table. Avoid dialect in favor of ANSI/ISO Standard SQL. You need to read and download the PDF for: 
https://www.simple-talk.com/books/sql-books/119-sql-code-smells/
Please, please learn why rows are not records. You do not even know what a key is or how to write a INTEGER NOT NULL(s, p) declaration. Allowing a table and column to have the same name is legal syntax and we regret not taking it out of the Standard. It is
stupid! How can a set also be an attribute of itself? But your DDL gave no attribute  properties, as per ISO-11179. 
Here is my attempt at repairs
CREATE TABLE CRT 
(crt_something INTEGER NOT NULL, 
 grd_something INTEGER NOT NULL, 
 PRIMARY KEY (crt_something, grd_something),
 gst_date DATE NOT NULL);
Here is how we write an insertion statement; you are still using Sybase syntax! Why did you pick the most ambiguous, non-ANSI date display format? 
INSERT INTO CRT 
VALUES 
 ( 7, 1900, '2000-01-01), 
 ( 7, 2100, '2010-01-01'), 
 ( 7, 2200, '2012-01-01'), 
 (19, 1900, '2002-01-01'), 
 (19, 2100, '2012-01-01'), 
 (19, 2200, '2012-02-02'),
 (24, 1900, '2013-01-01');
>> How I can get the MAX(gst_date) record [sic] of grd_something. If record [sic] of grd_something has more than one record [sic] then I need the one MAX(gst_date) record [sic] of every grd_something. <<
WITH X
(SELECT crt_something, grd_something, gst_date,
        MAX(gst_date) 
          OVER (PARTITION BY grd_something) AS gst_date_max
  FROM CRT)
 SELECT *
   FROM X
  WHERE gst_date_max = gst_date;
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