Forms :: Populate Data Block

i have created on query block , upon pressing the button there is a wehre clause in the block which will filter the records based on all alike items from two tables but my problem is , in one table there is no information of struct and in other there is struct information or data, what i want is even if i pass a parameter in the where clause all the records should be filtered.

CREATE TABLE OT_ACTUAL_ACT (ITEM_CODE VARCHAR2(30),ITEM_NAME VARCHAR2(30),WO VARCHAR2(12),STRUCT VARCHAR2(12))
INSERT INTO OT_ACTUAL_ACT(ITEM_CODE,ITEM_NAME,WO,STRUCT)
VALUES ('1001','HEA100X10','300',null);

[Code]...

I am getting this

ITEM_CODEITEM_NAMEWOSTRUCT
1002 HEA100X2230030010

i want all the records

ITEM_CODEITEM_NAMEWOSTRUCT
1002 HEA100X2230030010
1003 HEA100 300
1001 HEA100X10 300