[SQL] Argument variables for select

[Andreas Tille]

Hello,

I want to use the following construct in a stored function:

Create Function VarSelect ( varchar, varchar )
   returns int
   As '
     Declare num int ;
     
     Begin
       Select Into num Count(*) From $1 Where $2 ;
       return num;
     End ;
   ' language 'plpgsql' ;

Could someone please explain who to type the exact syntax so that
I can ship the table to select from as $1 and the condition to select
what as $2?  Or do I have to concatenate a string with the whole
select statement and how to call this string?  In MS SQL server this
could be done with 
   Exec ( query )

Kind regards

          Andreas.