How I can compare two fields of different tables ?

[adrianzazugmail.com]

Hi, Good night, I have problems compare two differents fields in two tables, first in table1 I have the field, days off, this field is string and the information appeer this: SD.

In the second table, the field is double and the information appeer this: 67.

I tryed whit a variable and I can compare the two fields with a if/else, (some this: if DL=71, else LM=12... ) but the value of the variable is not saved, when I  filter in the query, the variable not work. I tried with a subreport to pass the value of the variable to a parameter in the subreport, but no save the information. My question is: I can declare the variable in the query for to filter whit a WHERE? (WHERE $V!{CONDITION} <> 12)

PART OF MY CODE

SELECT *  FROM TABLE1  PART OF MY CODE  TABLE2 FIELDX=FIELDY

WHERE FIELDX<>FIELDY

ORDER BY NAME ASC