Multiple selects and comparisons in sql -

string sql = "     select name,             surname,             orderid,             customerid,             priority,             status,             date,             time      orders o      o.customerid in "             + "(select loggedin                  customers                  loggedin=1)"; 

i have 2 tables 1 called customer , 1 called orders. in customer table want retrieve people logged in system , match orders table see if have orders pending well. both of these tables contain customerid column contain same values. however, not sure how use , carry out logged in check in 1 statement. above 1 of attempts have made incorrect needs add join customerid's unsure carry out. in addition, sql driver using apache derby in case wondering

your query fine need select "customerid" @ end

 ... in (  select customerid  customers   loggedin=1 ) 

but recommend user joins. see users have pending orders:

select c.*  customers c inner join orders o  on o.customerid = c.customerid c.loggedid = 1 group c.customerid 

to see pending orders user:

select * orders o inner join customer c  on o.customerid = c.customerid , c.loggedid = 1