OUTER JOIN with filter

Hello,

Can anyone help me with the problem bellow ?

I want to have all the row in table "table_main" with the value in the table
"table_slave" (value or null if not exist)

It is possible to have the same result without sub-select in OUTER JOIN
(speed problem on big table) ?

Actualy this is what I make...

CREATE TABLE "table_main" (
"id" int4,
"some_field" varchar(100)
);

CREATE TABLE "table_slave" (
"id" int4,
"name" varchar(100),
"c1" varchar(30)
);

SELECT TM.some_field, TS.name
FROM table_main TM
LEFT OUTER JOIN (SELECT name FROM table_slave WHERE c1 = 'myvalue') TS
USING(id)

the request bellow is not correct:

SELECT TM.some_filed, TS.name
FROM table_main TM
LEFT OUTER JOIN table_slave TS USING(id)
WHERE (TS.c1 = 'myc1' OR TS.c1 IS NULL)

Many thanks,

Nicolas