We use NULLIF() for adding [1|0|null] according to the evalution of nullif('x','') into boolean columns. Where x is [1|0|null], which if it's an empty string (x='') then we add NULL cause NULLIF says if '' == '' then return NULL into boolean. An example wrapper function for this with an integer cast: CREATE FUNCTION nullif_always_int(text) RETURNS integer AS ' SELECT nullif($1,'''')::int; ' LANGUAGE SQL; I was hoping I could do something simliar with booleans if possible? ____________________________________________________ Start your day with Yahoo! - make it your home page http://www.yahoo.com/r/hs ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match