Re: Can an SQL common table expression be used for many different selects?

Ok, if you can afford a CTE.

If the scope is fetching from a specific position we use:
EXEC SQL
FETCH RELATIVE :W_Riga FROM Curs1 INTO :Wsql :Indnul;

HTH
--
Marco Facchinetti

Mr S.r.l.

Tel. 035 962885
Cel. 393 9620498

Skype: facchinettimarco


Il giorno mar 28 lug 2020 alle ore 18:36 Maria Lucia Stoppa <
mlstoppa@xxxxxxxxx> ha scritto:

@Marco
I tried as @Charles suggested, but it doesn't work: it returns the number
of fetched rows only instead of the total number of rows.

So far, I have successfully tested @Kyle suggestion to use SQL row_count()
function in reverse order.

Il giorno mar 28 lug 2020 alle ore 18:23 Marco Facchinetti <
marco.facchinetti@xxxxxxxxx> ha scritto:

Hi Maria, just answering the count() part of your question:

EXEC SQL
PREPARE S1 FROM :W_String;
EXEC SQL
DECLARE Curs1 INSENSITIVE SCROLL CURSOR FOR S1;
EXEC SQL
OPEN Curs1;
EXEC SQL
GET DIAGNOSTICS :Risposta.Recordtotali = DB2_NUMBER_ROWS;

HTH
--
Marco Facchinetti

Mr S.r.l.

Tel. 035 962885
Cel. 393 9620498

Skype: facchinettimarco


Il giorno mar 28 lug 2020 alle ore 11:17 Maria Lucia Stoppa <
mlstoppa@xxxxxxxxx> ha scritto:

Hi all,
Hope you are well.

A REST API I am working on returns data split into pages: many calls

are

necessary to get the complete set of data, but in this way, the user
doesn't wait too much for the first page. Data are retrieved within an

RPG

ILE service program by a static SQL statement which applies some

dynamic

filters that come within the request.

Everything works fine, except the same static SQL statement is run at

least

twice to know the total number of rows (a simple count(*)) and the rows
themselves page by page.
Now, on the same data retrieved by this SQL statement, others select
statements must be run to get some totals according to different group

by

clauses in order to present the data set distribution to the final

user.

I hardly accepted the idea of running the same SQL statement (which, by
the way, is pretty complex) at least twice to get both the total and

the

row, but I can't stand the idea of even more runs to get data

distribution.

There might be errors in my design of how the procedure should work,
nonetheless, I wonder if a single common table expression might be used
many times to serve many different select statements, as I would avoid

the

use of other solutions like global temporary tables.

Any suggestion is really appreciated.

Many thanks

--

Maria Lucia Stoppa
mlstoppa@xxxxxxxxx
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