Question

In this table I want to delete the oldest entry for userid 1, here the oldest entry is ghi 10/12/2011 11:20:22 i get the oldest entry by the datetime. How can I compare date time and do a delete in the same query. I want to compare the datetime entry for userid 1

delete from tbl_name where datetime is oldestentry and userid=1;

No    Name       DateTime              UserID
1     abv     12/12/2011 11:20:22         1
2     edf     11/12/2011 11:20:22         1
3     ghi     10/12/2011 11:20:22         1

Answer 1

This does not work in MySQL:

DELETE 
FROM tbl_name 
WHERE No = 
      ( SELECT No 
        FROM tbl_name 
        WHERE UserID = 1
        ORDER BY datetime ASC 
        LIMIT 1
      )

but this does:

DELETE 
FROM tbl_name 
WHERE UserID = 1
ORDER BY datetime ASC 
LIMIT 1