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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)
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