Question

I have a ms access mdb-file like this:

table Main:

int recordID
int status
int placement
bool @private
string category
string note
string description
string dueDate
bool completed
int priority
byte[] blob
bool repeatOnCompleteDate
string completeDate
bool alarmSet
string alarmTime
int alarmAdvance
string repeatStartDate
string repeatInfo

I would like to remove duplicate entries where description+note is the same so only one entry with the same description+note content remains. If there are two or more duplicates where some entries’ category is 0(beware it’s a string) remove this rather than the one whose category does not equal zero.

Fi.

Desc - Note - Cat
Hello - Test - 0
Hello - no - 3
Hello - Test - 0
Hello - Test - 4
Hello - Test - 0

Then one single Desc Hello with Note Test and with Category 4 should remain.

I found

delete from MyTable
where uniqueField not in
(select min(uniqueField) from MyTable T2
where T2.dupField=MyTable.dupField)

converted it to

delete from Main where Category not in (select min(Category) from Main T2 where T2.Description=Main.Description)

but that does not work.

Which MSACCESS SQL Command do you recommend?

Answer 1

There are number of sources available on net you may see here or here. You can also do this through query like

DELETE
FROM MyTable
WHERE ID NOT IN
(
SELECT MAX(ID)
FROM MyTable
GROUP BY DuplicateColumn1, DuplicateColumn2, DuplicateColumn3)