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Dynamically choosing a column in MySQL?
First, you need to prepare a query and then you need to execute the PREPARED statement to dynamically choose a column in MySQL.
Let us first create a table −
mysql> create table DemoTable ( EmployeeName varchar(100) ); Query OK, 0 rows affected (0.77 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable values('John Doe');
Query OK, 1 row affected (0.18 sec)Display all records from the table using select statement −
mysql> select *from DemoTable;
This will produce the following output −
+--------------+ | EmployeeName | +--------------+ | John Doe | +--------------+ 1 row in set (0.00 sec)
Let us now dynamically choose a column in MySQL −
mysql> set @dynamicQuery=CONCAT("SELECT ", (SELECT "EmployeeName from DemoTable"));
Query OK, 0 rows affected (0.00 sec)
mysql> select @dynamicQuery;
+---------------------------------------+
| @dynamicQuery |
+---------------------------------------+
| SELECT EmployeeName from DemoTable |
+---------------------------------------+
1 row in set (0.00 sec)
mysql> prepare myStatement from @dynamicQuery;
Query OK, 0 rows affected (0.00 sec)
Statement prepared
mysql> execute myStatement;This will produce the following output −
+--------------+ | EmployeeName | +--------------+ | John Doe | +--------------+ 1 row in set (0.00 sec)
Updated on: 25-Sep-2019
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