Set MySQL select in a custom variable

Let us first create a table −

mysql> create table DemoTable2013
   -> (
   -> Name varchar(20)
   -> );
Query OK, 0 rows affected (0.63 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable2013 values('Chris');
Query OK, 1 row affected (0.13 sec)

mysql> insert into DemoTable2013 values('David');
Query OK, 1 row affected (0.14 sec)

mysql> insert into DemoTable2013 values('Mike');
Query OK, 1 row affected (0.19 sec)

mysql> insert into DemoTable2013 values('Sam');
Query OK, 1 row affected (0.10 sec)

mysql> insert into DemoTable2013 values('Bob');
Query OK, 1 row affected (0.12 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable2013;

This will produce the following output −

+-------+
| Name  |
+-------+
| Chris |
| David |
| Mike  |
| Sam   |
| Bob   |
+-------+
5 rows in set (0.00 sec)

Here is the query to set MySQL SELECT statement in a custom variable −

mysql> set @query := (select count(*) from DemoTable2013);
Query OK, 0 rows affected (0.00 sec)

mysql> select Name
   -> from DemoTable2013
   -> where (@query := @query-1) = 0;

This will produce the following output −

+------+
| Name |
+------+
| Bob  |
+------+
1 row in set (0.00 sec)

AmitDiwan

Published on 06-Apr-2020 16:21:02