I have a specific recordset of 48 records (1 day over 1/2 hour slots).
I want to reduce the value of l
of the top 24 records (top by l
field DESC
) by a pre-known amount and all i have is the date and the amount I want to reduce by (a php var called $int).
Currently, I am reducing all 48 records as such:
UPDATE r SET l = l - $int WHERE thedate = '$kDate'
(updates 48 records)
How do I update the top 24?
Thanks in advance.
UPDATE r
SET l = l - $int
WHERE thedate = '$kDate'
order by l desc
limit 24
UPDATE r SET l = l - $int WHERE thedate = '$kDate'
ORDER BY l DESC
LIMIT 24
UPDATE r SET l = l - $int WHERE thedate = '$kDate' ORDER BY thedate DESC LIMIT 24
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