Query : problem in where section

I need to write a query like this :

SELECT S开发者_运维百科 , D1 , D2 , (D1+D2) as D_Sum , ( (D1+D2) / 
                 (X-(
                 SELECT SUM(T1+T2) 
                 FROM TBL1 
                 WHERE FCode=81 AND DCode=1 AND S<S
                 )) AS SSS 
FROM TBL1 
WHERE Salon=1 AND FCode=81 AND DCode=1

I have problem with S<S in where section in sub query . S<S likes FALSE and doesn't works .

First S are all of s in all of records in the table and second S is stored in each record .

S<S : I need select all records that their s is smaller than the s is stored in the record that now processed .

Give a name to the tables:

SELECT S , D1 , D1 , (D1+D2) as D_Sum , ( (D1+D2) / 
                 (X-(
                 SELECT SUM(innerTBL.T1+innerTBL.T2) 
                 FROM TBL1 innerTBL 
                 WHERE innerTBL.FCode=81 AND innerTBL.DCode=1 AND outerTBL.S<innerTBL.S
                 )) AS SSS 
FROM TBL1 outerTBL
WHERE Salon=1 AND FCode=81 AND DCode=1

Note: I should use the work "alias" instead of "name".