急，答对一定给分，刚得的分

Question

select ISNULL(B.name,A.username) tname, 
       ISNULL(B.addr,A.useraddress) TADDRESS,
       ISNULL(B.phone,A.userphone) tphone,
       ISNULL(B.email,A.useremail) temail
from edu_baomin A LEFT OUTER JOIN 
     (SELECT * FROM TCARD WHERE cardno IN(SELECT cardno FROM edu_baomin WHERE usertype = 1)) B ON A.cardno = B.cardno
where A.EDU_ID=3