Implement Dynamic SQL query inside a MySQL stored procedure?

For dynamic SQL query in a stored procedure, use the concept of PREPARE STATEMENT. Let us first create a table −

mysql> create table DemoTable2033    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> Name varchar(20)    -> ); Query OK, 0 rows affected (1.61 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable2033(Name) values('Chris'); Query OK, 1 row affected (0.85 sec) mysql> insert into DemoTable2033(Name) values('Bob'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable2033(Name) values('David'); Query OK, 1 row affected (0.24 sec) mysql> insert into DemoTable2033(Name) values('Mike'); Query OK, 1 row affected (0.12 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable2033;

This will produce the following output −

+----+-------+ | Id | Name  | +----+-------+ | 1  | Chris | | 2  | Bob   | | 3  | David | | 4  | Mike | +----+-------+ 4 rows in set (0.00 sec)

Following is the query to create a stored procedure and implement dynamic SQL −

mysql> delimiter // mysql> create procedure dynamic_query()    -> begin    -> set @query=concat("select *from DemoTable2033 where Id=3");    -> prepare st from @query;    -> execute st;    -> end    -> // Query OK, 0 rows affected (0.13 sec) mysql> delimiter ;

Call the stored procedure −

mysql> call dynamic_query();

This will produce the following output −

+----+-------+ | Id | Name | +----+-------+ | 3 | David | +----+-------+ 1 row in set (0.04 sec) Query OK, 0 rows affected (0.05 sec)