I’m a newie and I’m not really sure if MIN(My_Date) returns just one row if 2 or more dates are identical.
Reference is a FOREIGN KEY.
so to limit query:
SELECT MIN(Shipping_Date) FROM Com_Order WHERE Reference = 'X' and rownum = 1 GROUP BY Reference;
This second query seems to have same results just one value..
SELECT MIN(Shipping_Date) FROM Com_Order WHERE Reference = 'X';
I’m using JPA, so is it redundant to use rownum = 1 and GROUP BY Reference if I use
Query.creatQuery().getSingleResult()? Are the 2 queries the same?
The only difference between the two queries is that the 2nd will always return 1 row. Even if the table is empty or just has 0 rows with
reference=X, the result will be 1 row with
null in the
The first query will return no row in this case. The
and rownum=1 is useless and does not affect anything for the specific query.
Test at SQLfiddle.