外层查询能否使用内层查询中的表的某列,比如下面的语句,如何在SELECT中使用depart表的列
SELECT student_name
FROM student,depart
WHERE student.student_departid IN (SELECT depart_id FROM depart);
SELECT student_name
FROM student,depart
WHERE student.student_departid IN (SELECT depart_id FROM depart);
--外层查询是无法使用,内层查询的某列的,当然,直接把子查询写在SELECT 后面另说..
--如果要用到关联的某列的话,可以直接用连接来查询,不要使用子查询,示例如下:SELECT student_name,depart.depart_id
FROM student,depart
WHERE student.student_departid = depart.depart_id;
FROM student,depart
WHERE student.student_departid = depart.depart_id;
FROM student WHERE student.student_departid IN (SELECT depart_id FROM depart);
SELECT student_name
FROM student,depart
WHERE student.student_departid=depart.departid
AND student.student_departid IN (SELECT depart_id FROM depart);