On May 9, 2005, at 18:00, Zlatko Matic wrote:

This is a newbie question: what is the difference between using = and := in plpgsql function ?

In pl/pgsql,

:= is assignment
= is a logical comparison for equality

Some languages, such as perl, use = for assignment and == for logical comparison.

x = 1
is a boolean result

x := 1
gives x the value of 1

Quick example:

        x := 2; -- gives x the value of 2

        IF (x = 1) THEN -- x = 1 is false
                x := 3;  -- skipped
        END IF;
        RETURN X; -- returns 2

Again:
        x := 1; -- gives x the value of 1

        IF (x = 1) THEN -- x = 1 is true
                x := 3;  -- perform assignment
        END IF;
        RETURN x; -- returns 3

Hope this helps.

Michael Glaesemann
grzm myrealbox com


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