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How to select rows if initial ones are randomized and the rest ordered by criteria with MySQL?
For this, you can use ORDER BY CASE statement. Let us create a table −
mysql> create table DemoTable1926 ( Position varchar(20), Number int ); Query OK, 0 rows affected (0.00 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable1926 values('Highest',50);
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1926 values('Highest',30);
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1926 values('Lowest',100);
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1926 values('Lowest',120);
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1926 values('Lowest',90);
Query OK, 1 row affected (0.00 sec)Display all records from the table using select statement −
mysql> select * from DemoTable1926;
This will produce the following output −
+----------+--------+ | Position | Number | +----------+--------+ | Highest | 50 | | Highest | 30 | | Lowest | 100 | | Lowest | 120 | | Lowest | 90 | +----------+--------+ 5 rows in set (0.00 sec)
Here is the query to select rows if initial ones are randomized and rest ordered by criteria −
mysql> select * from DemoTable1926 order by Position desc,case Position when 'Highest' then rand() else Number end asc;
This will produce the following output −
+----------+--------+ | Position | Number | +----------+--------+ | Lowest | 90 | | Lowest | 100 | | Lowest | 120 | | Highest | 50 | | Highest | 30 | +----------+--------+ 5 rows in set (0.00 sec)
Updated on: 30-Dec-2019
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