SELECT all the newest record distinct keyword with a non null value in one column
Following on from this question SELECT the newest record with a non null value in one column
I know have a problem where I have this data
id | keyword | count | date
1 | ipod | 200 | 2009-08-02
2 | ipod | 250 | 2009-09-01
3 | ipod | 150 | 2009-09-04
4 | ipod | NULL | 2009-09-07
5 | apple | 100 | 2009-07-01
6 | apple | 98 开发者_如何学C| 2009-07-05
7 | apple | 500 | 2009-07-30
8 | itunes | NULL | 2009-08-30
9 | itunes | 50 | 2009-09-10
10 | itunes | NULL | 2009-09-15
And need a query which will fetch out rows 3, 7 and 9 Row which has the newest date and is non-null.
Use:
SELECT t.id,
t.keyword,
t.count,
t.date
FROM TABLE t
JOIN (SELECT t.keyword,
MAX(t.date) 'max_date'
FROM TABLE t
WHERE t.count IS NOT NULL
GROUP BY t.keyword) x ON x.keyword = t.keyword
AND x.max_date = t.date
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