Question

I’ve written a stored procedure. It’s working fine except taking the table name as input parameter.

Let see my proc in MySQL:

DELIMITER $$
USE `db_test`$$

DROP PROCEDURE IF EXISTS test_proc$$

CREATE DEFINER=`root`@`localhost` 
PROCEDURE `test_proc`(IN serviceName VARCHAR(10),IN newsInfoTable VARCHAR(100))
BEGIN                  
    SELECT COUNT(*) FROM newsInfoTable WHERE newsServiceName=serviceName;           
END$$

DELIMITER ;

Stored procedure calling parameters:

USE db_test;
CALL test_proc('abc','tbl_test_news');

Here the service name parameter is working fine. But if I include the newsInfoTable variable as table input parameter then a error shows.

Table ‘db_test.newsinfotable’ doesn’t exist

Why does this happen only for table parameter? How can I retrieve from this error or

How I pass a table name into a stored procedure as a parameter?

Answer 1

An SP cannot be optimized with a dynamic table name, so many DBs, MySQL included, don’t allow table names to be specified dynamically.

One way around this is to use Dynamic SQL.

CREATE DEFINER=`root`@`localhost` PROCEDURE `test_proc`(IN serviceName VARCHAR(10),IN newsInfoTable VARCHAR(100))
BEGIN                  
    SET @sql = CONCAT('SELECT COUNT(*) FROM ',newsInfoTable,' WHERE newsServiceName=?;'); 
    PREPARE s1 from @sql;
    SET @paramA = serviceName;
    EXECUTE s1 USING @paramA;
END$$