Performing group by

Question

Hi
Please help as how to get group by on selected rows.
I have a query, that results like this:-
a b c we are good
a b c ghy hgf hjgef
a b c ghfr urh urhg
I need the result as
a b c we are good
ghy hgf hjgef
ghfr urh urhg
Please help, as hot to get this.
Also suggest some good book to refer and get basics of writing sql query.
Thanks

Answer 1

Hi,
So you just want to hide this first 3 columns when they are the same as the first 3 columns of the preceding row, is that it?
Your front-end can probably do that easiest. For example, if you're using SQL*Plus:
BREAK  ON  col1  NODUPLICATES
BREAK  ON  col2  NODUPLICATES
BREAK  ON  col3  NODUPLICATESUse your column names in place of col1, col2 and col3.
NODUPLICATES is the default; you can just say "BREAK ON col1" if you want.
If you really have to do this in SQL, use the analytic LAG function to see what a value was on the previous row. Use CASE to return NULL if it's the same as the current row,
If you need help. post a little sample data (CREATE TABLE and INSERT statements) and the results you want from that data.
When you post the results, type these 6 characters:
\(all small letters, in curly brackets) before and after each section of formatted text; otherswise, this site will compress the spaces and nobody will be able to tell what's in what column.