A table function is a function that returns an entire set of rows and can be queried directly from the within a SQL statement as if it were true database table. Whereas pipeline function is similar but returns the data as it is constructed rather than all at once.

e.g.

CREATE TYPE MyType AS OBJECT (
field1 Number
field2 Varchar2(50);

CREATE TYPE MyTypeList AS TABLE OF MyType;

CREATE OR REPLACE FUNCTION PipelineMe
RETURN MytypeList PIPELINED AS V_MyType Mytype;
BEGIN
FOR V_count IN 1..20 LOOP
V_Mytype : MyType (V_count ' Row ' || V_count);
PIPE ROW (V_Mytype);
ENDLOOP;
RETURN;
END PipelineMe;