Getting Newest Record from a table using mysql - mysql

Question

This has to be a no brainer, but I am stumped. I'm used to using aggregate 'FIRST' in MsAccess, but MySql has no such thing.
Here is a simple table. I want to return the most recent record based on the date,
for each unique 'group ID'. I need the three records in yellow.
I was asked to add my full query. I tried one of the suggestions using the JOIN feature replacing 't' with the temp table name, but it failed to work. "Can't reopen table 't'"
The code is below. I know it's ugly, but it does return the correct data set.
I cleaned up the code a bit and added the JOIN code. Error: "Can't reopen table 't'"
enter code here
DROP TABLE IF EXISTS `tmpMaxLookupResults`;
create temporary table tmpMaxLookupResults
as
SELECT
REPORTS.dtmReportCompleted,
RESULTS.lngMainReport_ID, RESULTS.lngLocationGroupSub_ID
FROM
(tbl_010_040_ProcedureVsTest_Sub as ProcVsSub
INNER JOIN tbl_010_050_CheckLog_RESULTS as RESULTS
ON (ProcVsSub.lngLocationGroupSub_ID = RESULTS.lngLocationGroupSub_ID)
AND (ProcVsSub.lngProcedure_ID = RESULTS.lngProcedure_ID)
AND (ProcVsSub.lngItemizedTestList_ID = RESULTS.lngItemizedTestList_ID)
AND (ProcVsSub.strPasscodeAdmin = RESULTS.strPasscodeAdmin)
AND (ProcVsSub.strCFICode = RESULTS.strCFICode))
INNER JOIN
tbl_000_010_MAIN_REPORT_INFO as REPORTS ON (RESULTS.lngPCC_ID =
REPORTS.lngPCC_ID)
AND (RESULTS.lngProcedure_ID = REPORTS.lngProcedure_ID)
AND (RESULTS.lngMainReport_ID = REPORTS.idMainReport_ID)
AND (RESULTS.strPasscodeAdmin = REPORTS.strPasscodeAdmin)
AND (RESULTS.strCFICode = REPORTS.strCFICode)
WHERE
(((RESULTS.lngProcedure_ID) = 143)
AND ((RESULTS.dtmExpireDate) IS NOT NULL)
AND ((RESULTS.strCFICode) = 'ems'))
GROUP BY RESULTS.lngMainReport_ID, RESULTS.lngLocationGroupSub_ID
ORDER BY (REPORTS.dtmReportCompleted) DESC;
SELECT t.*
FROM tmpMaxLookupResults AS t
JOIN (
SELECT lngLocationGroupSub_ID,
MAX(dtmReportCompleted) AS max_date_completed
FROM tmpMaxLookupResults
GROUP BY lngLocationGroupSub_ID ) AS dt
ON dt.lngLocationGroupSub_ID = t.lngLocationGroupSub_ID AND
dt.max_date_completed = t.dtmReportCompleted
enter code here

Answer 1

Try this
SELECT
tn.*
FROM
tableName tn
RIGHT OUTER JOIN
(
SELECT
groupId, MAX(date_completed) as max_date_completed
FROM
tableName
GROUP BY
groupId
) AS gt
ON
(gt.max_date_completed = nt.date_completed AND gt.groupId = nt.groupId)

Answer 2

You can use the following SQL.
select * from table1 order by date_completed desc Limit 1;

Answer 3

Use Order By
SELECT *
FROM table_name
ORDER BY your_date_column_name
DESC
LIMIT 1

Answer 4

In a Derived Table, get the maximum date_completed value for every group_id.
Join this result-set back to the main table, in order to get the complete row corresponding to maximum date_completed value for every group_id
Try the following query:
SELECT t.*
FROM your_table_name AS t
JOIN (
SELECT group_id,
MAX(date_completed) AS max_date_completed
FROM your_table_name
GROUP BY group_id
) AS dt
ON dt.group_id = t.group_id AND
dt.max_date_completed = t.date_completed