Substitute a variable in PL/PGSQL. - Mailing list pgsql-general

From Steve Martin
Subject Substitute a variable in PL/PGSQL.
Date
Msg-id 4885632A.4020307@nec.co.nz
Whole thread Raw
Responses Re: Substitute a variable in PL/PGSQL.
Re: Substitute a variable in PL/PGSQL.
List pgsql-general
Hi,

I am trying to create a PL/PGSQL function to return the values of the
fields in a record, e.g. 1 value per row in the output of the function.

How do you substitute a variable?

Test case:

CREATE TABLE test(col1 text, col2 text, col3 text, col4 text, col5 text,
col6 text, col7 text, col8 text, col9 text, col10 text);
INSERT INTO test VALUES ('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j');
INSERT INTO test VALUES ('A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J');
INSERT INTO test VALUES ('1', '2', '3', '4', '5', '6', '7', '8', '9', '10');

CREATE OR REPLACE FUNCTION testfunc() RETURNS SETOF text AS $$
DECLARE
    ted varchar;
    bob RECORD;
BEGIN
    FOR bob IN SELECT * FROM test LOOP
        FOR i IN 1..10 LOOP
            ted := 'bob.col' || i;
            RETURN NEXT ted;
        END LOOP;
    END LOOP;
    RETURN;
END
$$ LANGUAGE plpgsql;

test=> select * from testfunc();
 testfunc
-----------
 bob.col1
 bob.col2
 bob.col3
 bob.col4
 bob.col5
 bob.col6
 bob.col7
 bob.col8
 bob.col9
 bob.col10
 bob.col1
 bob.col2
 bob.col3
 bob.col4
 bob.col5
 bob.col6
 bob.col7
 bob.col8
 bob.col9
 bob.col10
 bob.col1
 bob.col2
 bob.col3
 bob.col4
 bob.col5
 bob.col6
 bob.col7
 bob.col8
 bob.col9
 bob.col10
(30 rows)

test=>


Or:
CREATE OR REPLACE FUNCTION testfunc() RETURNS SETOF text AS $$
DECLARE
    bob RECORD;
    ted TEXT;
BEGIN
    FOR i IN 1..10 LOOP
        ted := 'col' || i;
        FOR bob IN SELECT ted FROM test LOOP
            RETURN NEXT bob;
        END LOOP;
    END LOOP;
    RETURN;
END
$$ LANGUAGE plpgsql;
test=> select * from testfunc();
 testfunc
----------
 (col1)
 (col1)
 (col1)
 (col2)
 (col2)
 (col2)
 (col3)
 (col3)
 (col3)
 (col4)
 (col4)
 (col4)
 (col5)
 (col5)
 (col5)
 (col6)
 (col6)
 (col6)
 (col7)
 (col7)
 (col7)
 (col8)
 (col8)
 (col8)
 (col9)
 (col9)
 (col9)
 (col10)
 (col10)
 (col10)
(30 rows)

test=>

Or is there another way other than using another procedural language.

Thanks - Steve M.



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