为了将行选择与列选择结合起来，我们可以使用“WHERE”子句。例如，我们有下面的表格 -

mysql> Select * from Student;
+--------+--------+--------+
| Name   | RollNo | Grade  |
+--------+--------+--------+
| Gaurav | 100    | B.tech |
| Aarav  | 150    | M.SC   |
| Aryan  | 165    | M.tech |
+--------+--------+--------+
3 rows in set (0.00 sec)

现在，以下查询将展示如何使用 WHERE 子句将行选择与列选择结合起来。

mysql> Select Name, RollNo, Grade from Student where Grade='M.Sc' or Grade='B.Tech';
+--------+--------+--------+
| Name   | RollNo | Grade  |
+--------+--------+--------+
| Gaurav | 100    | B.tech |
| Aarav  | 150    | M.SC   |
+--------+--------+--------+
2 rows in set (0.00 sec)