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

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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