MS Access - Data type mismatch - simple integer comparison - ms-access

Question

I just cannot wrap my head around why I am getting this error?
"Data type mismatch in criteria expression."
SELECT * INTO Updated FROM (
SELECT a.*,
date() AS [Today],
DateValue([Last_Updated]) as [LastUpDateDate],
int(datediff("d", date(), DateValue([Last_Updated]))) as [mydatediff]
FROM Prior AS a
WHERE a.[Last_Updated] is not null
) t
WHERE t.[mydatediff] >= 1;
I just want a simple comparison of two integers and I keep getting the type mismatch error.

Answer 1

If Last_Updated is text, it probably holds some invalid date expressions.
Try using IsDate to filter those out:
SELECT * INTO Updated
FROM
( SELECT
a.*,
Date() AS [Today],
DateValue([Last_Updated]) AS [LastUpDateDate],
DateDiff("d", Date(), DateValue([Last_Updated])) AS [mydatediff]
FROM
Prior AS a
WHERE
IsDate(a.[Last_Updated])
) t
WHERE
t.[mydatediff] >= 1;
Alternatively, filter the subquery:
SELECT
t.*,
Date() AS [Today],
DateValue(t.[Last_Updated]) AS [LastUpDateDate],
DateDiff("d", Date(), DateValue(t.[Last_Updated])) AS [mydatediff]
INTO
Updated
FROM
( SELECT *
FROM Prior
WHERE IsDate([Last_Updated])
) t
WHERE
DateDiff("d", Date(), DateValue(t.[Last_Updated])) >= 1;
Solution
The trick is to force the subquery to finalise before retrieving its records. That can be done with DISTINCT:
SELECT *
FROM (
SELECT DISTINCT
Prior.Id,
DateValue([Last_Updated]) AS LastUpDateDate,
DateDiff("d",Date(),DateValue([Last_Updated])) AS mydatediff
FROM
[Prior]
WHERE
IsDate([Last_Updated]) <> False
) AS T
WHERE T.mydatediff >= 1;
Sample:
Output: