এজন্য CHAR_LENGTH() ব্যবহার করুন। র্যান্ডম রেকর্ডের জন্য RAND()।
টেবিল তৈরি করা
mysql> create table DemoTable (Subject text); Query OK, 0 rows affected (0.61 sec)
রেকর্ড ইনসার্ট করা
mysql> insert into DemoTable values('C');
Query OK, 1 row affected (0.16 sec)
mysql> insert into DemoTable values('MySQL');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable values('Java');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable values('MongoDB');
Query OK, 1 row affected (0.59 sec)
mysql> insert into DemoTable values('RubyOnRails');
Query OK, 1 row affected (0.25 sec)
mysql> insert into DemoTable values('C++');
Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable values('Python');
Query OK, 1 row affected (0.20 sec)
সকল রেকর্ড প্রদর্শন
mysql> select *from DemoTable;
আউটপুট
+-------------+ | Subject | +-------------+ | C | | MySQL | | Java | | MongoDB | | RubyOnRails | | C++ | | Python | +-------------+ 7 rows in set (0.00 sec)
নির্দিষ্ট দৈর্ঘ্যের ৩টি র্যান্ডম রেকর্ড সিলেক্ট করার কোয়েরি
mysql> select *from (select *from DemoTable WHERE CHAR_LENGTH(Subject) = 7 ORDER BY RAND() LIMIT 1 ) tbl UNION (select *from DemoTable WHERE CHAR_LENGTH(Subject) = 11 ORDER BY RAND() LIMIT 1 ) UNION (select *from DemoTable WHERE CHAR_LENGTH(Subject) = 5 ORDER BY RAND() LIMIT 1 );
আউটপুট
+-------------+ | Subject | +-------------+ | MongoDB | | RubyOnRails | | MySQL | +-------------+ 3 rows in set (0.04 sec
