How to get the most recent record of multiple of the same records in a table while joining another table? - sql

Question

SELECT tblSign.sigdate,tblSign.sigtime,tblSign.sigact,tblSign.esignature,tblEmpl.fname,tblEmpl.lname,tblEmpl.location, tblEmpl.estatus,tblLocs.unit,tblLocs.descript,TblLocs.addr1,tblLocs.city,tblLocs.state, tblLocs.zip
FROM tblEmpl
LEFT JOIN tblSign
ON tblSign.eight_id = tblEmpl.eight_id
AND tblSign.formid = '9648'
AND tblSign.sigact <> 'O'
AND tblSign.sigdate >= '2022-11-01'
LEFT JOIN tblLocs
ON tblEmpl.location = tblLocs.location
WHERE tblEmpl.estatus = 'A'
AND tblEmpl.location = '013'
ORDER BY
tblSign.sigdate ASC;
My table Sign has multiple records with the same eight_id so Im just trying to join tables getting the most recent record from tblSign besides multiple records
Data I get
Sigdate
fname
lname
location
sigact
2022-11-01
Bill
Lee
023
A
2022-10-01
Bill
Lee
023
A
2022-11-01
Carter
Hill
555
A
This is what I want :
Sigdate
fname
lname
location
sigact
2022-11-01
Bill
Lee
023
A
2022-11-01
Carter
Hill
555
A

Answer 1

Start by getting into better code-writing habits. Having all column names in one long string is horrible for readability and consequently troubleshooting. You can select the most recent record from a table by using a ROW_NUMBER function. I took your code, cleaned it up, added a derived table and in the derived table added a ROW_NUMBER function. I can't validate that the query works because you didn't post example source data from your tblEmpl, tblSign, and tblLocs tables. I'm not sure if the AND tblSign.sigact <> 'O' is valid in the derived table because it's not clear if you were trying to just limit the date range or that was your attempt to retrieve the most recent date.
SELECT
tblSign.sigdate
, tblSign.sigtime
, tblSign.sigact
, tblSign.esignature
, tblEmpl.fname
, tblEmpl.lname
, tblEmpl.location
, tblEmpl.estatus,tblLocs.unit
, tblLocs.descript
, TblLocs.addr1
, tblLocs.city
, tblLocs.state
, tblLocs.zip
FROM tblEmpl
LEFT JOIN (
SELECT *
--Used to order the records for each eight_id by the date.
--Most recent date for each eight_id will have row_num = 1.
, ROW_NUMBER() OVER(PARTITION BY eight_id ORDER BY sigdat DESC) as row_num
FROM tblSign as ts
WHERE tblSign.formid = '9648'
AND tblSign.sigact <> 'O'
AND tblSign.sigdate >= '2022-11-01' --Not clear if this is just to limit results or an attempt to get most recent date in the failed original code.
) as ts
ON ts.eight_id = tblEmpl.eight_id
AND ts.row_num = 1 --Use to limit to most recent date.
LEFT JOIN tblLocs
ON tblEmpl.location = tblLocs.location
WHERE tblEmpl.estatus = 'A'
AND tblEmpl.location = '013'
ORDER BY
tblSign.sigdate ASC

Answer 2

You use ROW_NUMBER to get the last entry in my case for every esignature, as i thought this must be unique
WITH CTE AS
(SELECT
tblSign.sigdate,
tblSign.sigtime,
tblSign.sigact,
tblSign.esignature,
tblEmpl.fname,
tblEmpl.lname,
tblEmpl.location,
tblEmpl.estatus,
tblLocs.unit,
tblLocs.descript,
TblLocs.addr1,
tblLocs.city,
tblLocs.state,
tblLocs.zip,
ROW_NUMBER() OVER(PARTITION BY tblSign.esignature ORDER BY tblSign.sigdate DESC) rn
FROM
tblEmpl
LEFT JOIN
tblSign ON tblSign.eight_id = tblEmpl.eight_id
AND tblSign.formid = '9648'
AND tblSign.sigact <> 'O'
AND tblSign.sigdate >= '2022-11-01'
LEFT JOIN
tblLocs ON tblEmpl.location = tblLocs.location
WHERE
tblEmpl.estatus = 'A'
AND tblEmpl.location = '013')
SELECT sigdate,
sigtime,
sigact,
esignature,
fname,
lname,
location,
estatus,
unit,
descript,
addr1,
city,
state,
zip
WHERE rn = 1
ORDER BY sigdate ASC;