make relasion with one query with other query

[riantoaji]

hello
i am a beginner here,i am sorry if ask a question.
i have a problem with my database,i have a query A.i want to find a datediff with one field in my table and so i spread with 2 queries,query 1 and query 2 and then i make a relation between query 1 and 2,and then i got a datediff in other query"query 3".and i want to put 1 field from query 3 to query A and if i run i got the double record. give me the best solution please.

[ranman256]

set the last query property to unique values = true
(no duplicates)