create or replace function exc_using(int, text) returns int as
    $$
        declare i int;
        begin
        for i in execute 'select * from generate_series(1,$1) ' using $1 1 loop
            raise notice '% ', i;
            raise notice 'i   i *3: % ', i   i * 3;
        end loop;
        execute 'select $2   $2 * 3   length($1) '
            into i using $2, $1;
        return i;
        end
    $$
language plpgsql;

seems A

    execute 'select $2   $2 * 3   length($1) '
        into i using $2, $1;
    return i;

is the same as: B

    execute 'select $1   $1 * 3   length($2) '
        into i using $1, $2;
    return i;

My preception is that $2 Absolutely refer to function second argument that data type is text. but seems plpgsql $[position] is relative. But I cannot get manual reference for this edge case.

CodePudding user response：

Of course they are relative. What else would they be? But what are they relative to?

Inside the EXECUTE string, the $1 and $2 are relative to the USING. Outside, they are relative to the function parameters.