I'm sure this question is obvious, but I've been fiddling with an increasingly complex set of subqueries for the last hour or so and getting nowhere.
I need to select a bunch of ID's from a ta开发者_如何学JAVAble where the last date for that record is before a given date. I was trying:
SELECT id_field WHERE max(date_field) < 'some date'
But getting 'can't have aggregate in where field'. I've considered that I could SELECT where there are no dates above a certain date, but at this point my brain is waving it's little white flag.
Thanks.
SELECT id_field
, max(date_field)
FROM tbl
GROUP BY id_field
HAVING max(date_field) < 'some date'
SELECT id_field
FROM tbl
GROUP BY id_field
HAVING max(date_field) < 'some date'
Use HAVING
instead of WHERE
. HAVING
is like a where for grouped values.
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