I am trying write a SQL query to pull the data from 3 tables using JOINS on basis of common HashKey and I want to take all the updated records from 3rd table based on the load date(last increment/recent records) using SQL.
I have tried below SQL query but I am not able to get the recent record from third table.
x
SELECT
tab1.TennisID
tab1.TennisHashKey
tab3.LoadDate
tab2.TennisType
tab3.Clicks
tab3.Hit
tab3.Likes
fROM table1 tab1
LEFT JOIN table2 tab2
ON tab1.TennisHashKey = tab2.TennisHashKey
LEFT JOIN (SELECT * FROM Table3 WHERE LoadDate = (SELECT TOP 1 LoadDate FROM Table 3 ORDER BY LoadDate Desc)) tab3
ON tab2.TennisHashKey = tab3.TennishHashKey
I have matching number of records in Table 1 and Table 2, but there are multiple rows for same hashkey in Table3 based on loadDate.
Please provide your suggestion on this.
Thanks
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Answer
Use ROW_NUMBER()
to join only the most recent row from Table3.
SELECT
tab1.TennisID
, tab1.TennisHashKey
, tab3.LoadDate
, tab2.TennisType
, tab3.Clicks
, tab3.Hit
, tab3.Likes
FROM table1 tab1
LEFT JOIN table2 tab2
ON tab1.TennisHashKey = tab2.TennisHashKey
LEFT JOIN (
SELECT *
, ROW_NUMBER() OVER (PARTITION BY TennisHashKey ORDER BY LoadDate DESC) rn
FROM Table3
) tab3
ON tab2.TennisHashKey = tab3.TennishHashKey
AND rn = 1;