Sql Functions

Can anyone see what the problem is with this sql function? When I run the
query outside the function I get the expected result. It seems that SQL
functions do not like the keyword 'OR'. Does anyone know if this is a known
bug?

Thanks, Randy

Here are the tables:

create table T1(
t1c1 integer primary key,
t1c1d varchar(20)
);
create table T2(
t2c1 char(20) primary key,
t2c1d varchar(200)
);
create table T3(
t3c1 char(20) primary key,
t3c1d varchar(200)
);
create table T4(
t4c1 char(20) references T3,
t4c2 char(20) references T2,
t4c3 integer references T1
);
create table T5(
t5c1 char(20) references T3,
t5c2 char(20) references T3,
t5c3 integer references T1
);
create table T6(
t6c1 char(10),
t6c2 char(20) references T3
);

Sample Data:
T1:
t1c1 | t1c1d
----------+----------------------
0 | T1R0
1 | T1R1
2 | T1R2

T2:
t2c1 | t2c1d
-----------+---------------------------------------------------------------------------------------------------
123 | stuff
456 | stuff
789 | stuff
0ab | stuff
cde | stuff

T3:
t3c1 | t3c1d
-------+-----------------------------------------------------------------------------
a1 | stuff
b2 | stuff
c3 | stuff

T4:
t4c1 | t4c2 | t4c3
----------+---------+------------
b2 | 456 | 0
a1 | a1 | 3

T5:
t5c1 | t5c2 | t5c3
-------+-----------+---------------
c3 | b2 | 2

T6:
t6c1 | t6c2
---------+----------------------
abc | a1
def | b2
ghi | c3

SQL query that works from psql:

select T4.t4c3 from T4, T5, T6 where
((T6.t6c2 = T4.t4c1 and T6.t6c1 = 'ghi') or
(T5.t5c2 = T4.t4c1 and T6.t6c2 = T5.t5c1 and T6.t6c1 = 'ghi')) and
(T4.t4c2 = '456')
union
select T5.t5c3 from T4, T5, T6
where
(T4.t4c2 = '456') and
(T5.t5c2 = T4.t4c1 and T6.t6c2 = T5.t5c1 and T6.t6c1 = 'ghi')
;
Returns:
t4c3
--------
1
2
(2 rows)
If I replace ghi with def
Returns:
t4c3
--------
1
(1 row)
If I replace ghi with abc
Returns:
t4c3
--------
3
(1 row)

Here is the function as I originally had it:

create or replace function func1(varchar, varchar) returns setof
integer as
'select T4.t4c3 from T4, T5, T6 where
((T6.t6c2 = T4.t4c1 and T6.t6c1::varchar = $1) or
(T5.t5c2 = T4.t4c1 and T6.t6c2 = T5.t5c1 and T6.t6c1::varchar = $1)) and
(T4.t4c2::varchar = $2)
union
select T5.t5c3 from T4, T5, T6
where
(T4.t4c2::varchar = $2) and
(T5.t5c2 = T4.t4c1 and T6.t6c2 = T5.t5c1 and T6.t6c1::varchar = $1)
;' language sql;

select func1('abc', '456'); returns:
func1
-------
(0 rows)
select func1('def', '456'); returns:
func1
-------
(0 rows)
select func1('ghi', '456'); returns:
func1
-------
2
(1 row)

Here is the function as I have it now that returns the same values as the sql
query statement above:

create or replace function func1(varchar, varchar) returns setof
integer as
'
select T5.t5c3 from T4, T5, T6
where
(T4.t4c2::varchar = $2) and
(T5.t5c2 = T4.t4c1 and T6.t6c2 = T5.t5c1 and T6.t6c1::varchar = $1)
union
select T4.t4c3 from T4, T5, T6
where
(T4.t4c2::varchar = $2) and
(T5.t5c2 = T4.t4c1 and T6.t6c2 = T5.t5c1 and T6.t6c1::varchar = $1)
union
select T4.t4c3 from T4, T5, T6
where
(T4.t4c2::varchar = $2) and (T6.t6c2 = T4.t4c1 and T6.t6c1::varchar = $1)
union
select T4.t4c3 from T4, T5, T6
where
(T4.t4c2 = ''a1'') and (T6.t6c2 = T4.t4c1 and T6.t6c1::varchar = $1)
;
' language sql;