Обсуждение: Function that returns Boolean

Hi,
This is a simple function that returns a boolean ..

create or replace function check_value( newValue IN VARCHAR,
                    oldValue IN VARCHAR ) RETURN BOOLEAN
as
'
BEGIN
    IF ( newValue != oldValue)
        then return true;
    else
        return false;
     END IF;
END;
'
LANGUAGE 'plpgsql'

But I get this error...what is wrong with this ?

[Error] Script lines: 1-13 -------------------------
 ERROR: syntax error at or near "RETURN"
 Line: 2

Thanks
Sharmila

Its a typo..it should be "RETURNS BOOLEAN" and not "RETURN BOOLEAN"
-Sharmila

--- On Mon, 2/23/09, SHARMILA JOTHIRAJAH <sharmi_jo@yahoo.com> wrote:

> From: SHARMILA JOTHIRAJAH <sharmi_jo@yahoo.com>
> Subject: Function that returns Boolean
> To: "General postgres mailing list" <pgsql-general@postgresql.org>
> Date: Monday, February 23, 2009, 12:39 PM
> Hi,
> This is a simple function that returns a boolean ..
>
> create or replace function check_value( newValue IN
> VARCHAR,
>                     oldValue IN VARCHAR ) RETURN BOOLEAN
> as
> '
> BEGIN
>     IF ( newValue != oldValue)
>         then return true;
>     else
>         return false;
>      END IF;
> END;
> '
> LANGUAGE 'plpgsql'
>
> But I get this error...what is wrong with this ?
>
> [Error] Script lines: 1-13 -------------------------
>  ERROR: syntax error at or near "RETURN"
>  Line: 2
>
> Thanks
> Sharmila

SHARMILA JOTHIRAJAH <sharmi_jo@yahoo.com> writes:
> create or replace function check_value( newValue IN VARCHAR,
>                     oldValue IN VARCHAR ) RETURN BOOLEAN

Should be RETURNS BOOLEAN.

You might want to fix whatever client code you are using so that it
shows the error cursor, which would certainly have helped direct
your attention to the right place instead of the wrong one.  What
I see in psql is

ERROR:  syntax error at or near "RETURN"
LINE 2:                     oldValue IN VARCHAR ) RETURN BOOLEAN
                                                  ^


            regards, tom lane

----- "SHARMILA JOTHIRAJAH" <sharmi_jo@yahoo.com> wrote:

> Hi,
> This is a simple function that returns a boolean ..
>
> create or replace function check_value( newValue IN VARCHAR,
>                     oldValue IN VARCHAR ) RETURN BOOLEAN
                                            ^^^^^^ RETURNS
> as
> '
> BEGIN
>     IF ( newValue != oldValue)
>         then return true;
>     else
>         return false;
>      END IF;
> END;
> '
> LANGUAGE 'plpgsql'
>
> But I get this error...what is wrong with this ?
>
> [Error] Script lines: 1-13 -------------------------
>  ERROR: syntax error at or near "RETURN"
>  Line: 2
>
> Thanks
> Sharmila
>
>
Adrian Klaver
aklaver@comcast.net

On Mon, Feb 23, 2009 at 9:39 AM, SHARMILA JOTHIRAJAH
<sharmi_jo@yahoo.com> wrote:

>    IF ( newValue != oldValue)

One good piece of advice that Tom Lane pointed out to me was:

IF ( newValue IS DISTINCT FROM oldValue )

is better due to (what may be) the unexpected results of equality
testing when NULL values are thrown into the mix.


--
Regards,
Richard Broersma Jr.

Visit the Los Angeles PostgreSQL Users Group (LAPUG)
http://pugs.postgresql.org/lapug

On Mon, Feb 23, 2009 at 09:39:01AM -0800, SHARMILA JOTHIRAJAH wrote:
> Hi,
> This is a simple function that returns a boolean ..

This should be an SQL function, as it doesn't do anything you need (or
would even find convenient) for a more procedural language to do:

CREATE OR REPLACE FUNCTION check_value(newValue TEXT, oldValue TEXT)
RETURNS BOOLEAN
LANGUAGE SQL
AS $$ SELECT $1 IS DISTINCT FROM $2 $$;

As others have pointed out, IS DISTINCT FROM covers the case where one
or more of the arguments is a NULL.

Cheers,
David.
>
> create or replace function check_value( newValue IN VARCHAR,
>                     oldValue IN VARCHAR ) RETURN BOOLEAN
> as
> '
> BEGIN
>     IF ( newValue != oldValue)
>         then return true;
>     else
>         return false;
>      END IF;
> END;
> '
> LANGUAGE 'plpgsql'
>
> But I get this error...what is wrong with this ?
>
> [Error] Script lines: 1-13 -------------------------
>  ERROR: syntax error at or near "RETURN"
>  Line: 2
>
> Thanks
> Sharmila
>
>
>
>
> --
> Sent via pgsql-general mailing list (pgsql-general@postgresql.org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-general

--
David Fetter <david@fetter.org> http://fetter.org/
Phone: +1 415 235 3778  AIM: dfetter666  Yahoo!: dfetter
Skype: davidfetter      XMPP: david.fetter@gmail.com

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