ใช้ GROUP BY LENGTH(column) HAVING LENGTH(column) < n กรองกลุ่มตามความยาว
สร้างตารางและเพิ่มหัวข้อ
mysql> create table DemoTable ( Title text );
Query OK, 0 rows affected (0.39 sec)
mysql> insert into DemoTable values('Introduction to MySQL'); Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable values('Introduction to Java'); Query OK, 1 row affected (0.09 sec)
mysql> insert into DemoTable values('Introduction to SQL'); Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable values('Introduction to Python'); Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable values('Introduction to SQL'); Query OK, 1 row affected (0.09 sec)
mysql> insert into DemoTable values('Introduction to Java'); Query OK, 1 row affected (0.13 sec)
คิวรีกรองความยาวน้อยกว่า 21 ตัวอักษร
mysql> select * from DemoTable group by length(Title) having length(Title) < 21;
+----------------------+ | Title | +----------------------+ | Introduction to SQL | | Introduction to Java | +----------------------+ 2 rows in set (0.00 sec)
ความยาว: 'Introduction to SQL' = 19, 'Introduction to Java' = 20, 'Introduction to MySQL' = 21, 'Introduction to Python' = 22
