Displaying a table based on where clause matching the field

Question

i am having a table named Vacancies  the fields here are Category,CompanyName,Designation,etcand another table named JS_Professional_Detail  the fields here are FunctionalArea, TotalExperience,keyskills,etc..
I want to display the table of vacancies where the Vacancies.Category shoul match the JS_Professional_Detail.FunctionalArea
The code i tried is
 SelectCommand="SELECT Vacancies.Category, Vacancies.CompanyName, Vacancies.RequiredExperience, Vacancies.Designation, Vacancies.RequiredEducation, Vacancies.RequiredAge, Vacancies.RequiredGender, Vacancies.MinimumJoiningTime, JS_Professional_Detail.FunctionalArea FROM Vacancies   FULL  OUTER JOIN JS_Professional_Detail ON Vacancies.Category = JS_Professional_Detail.FunctionalArea ">
                    where Vacancies.Category=JS_Professional_Detail.FunctionalArea">
but i need to display the vacany table based on the ctegory of the loginned candidate. based on the username i need to select category and match it with the vacancy and then display it thank you