How to get MYSQL dynamic query using stored procedure? - mysql

I am trying to run the dynamic query using a stored procedure in which I am sending the where condition case for example.
My sample stored procedure is shown here:
CREATE PROCEDURE `Storedproc`(IN getwhereconditon varchar(1000))
BEGIN
set #param=getwhereconditon ;
SET #S=concat('Select * from table where (1)',#param);
PREPARE stmt1 FROM #s;
EXECUTE stmt1;
END
Here my stored procedure's name is Storedproc in which I am passing the where condition details and when I call my stored procedure I am getting this error
Error Code: 1064. You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '0tablecol=1' at line

Try
DELIMITER //
CREATE PROCEDURE myproc(IN _where VARCHAR(512))
BEGIN
SET #sql = 'SELECT * FROM table1';
IF COALESCE(_where, '') <> '' THEN
SET #sql = CONCAT(#sql, ' WHERE ', _where);
END IF;
PREPARE stmt FROM #sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END //
DELIMITER ;
or
DELIMITER //
CREATE PROCEDURE myproc(IN _where VARCHAR(512))
BEGIN
SET #sql = CONCAT('SELECT * FROM table1', COALESCE(CONCAT(' WHERE ', NULLIF(_where, '')), ''));
PREPARE stmt FROM #sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END //
DELIMITER ;
Sample usage:
CALL myproc(NULL);
CALL myproc('name=''John''');
CALL myproc('age > 25');
CALL myproc('age < 28 OR age > 30');
Here is SQLFiddle demo

Related

How Do I Use Dynamic SQL (MySQL) To Store The Result of a Query Into a Local Variable?

In the procedure I'm writing I need to store the result of a dynamic SQL query into a local variable. Something like this:
DELIMITER //
CREATE PROCEDURE test_maxsum(uid varchar(25))
BEGIN
DECLARE maxsum int;
SET #SQL = CONCAT('SELECT MAX(sum_val) FROM ', uid);
PREPARE stmt FROM #SQL;
EXECUTE stmt INTO maxsum;
DEALLOCATE PREPARE stmt;
SELECT maxsum;
END//
DELIMITER ;
Local variables cannot be assigned in prepared statements. You can use user-defined variables though:
DELIMITER //
CREATE PROCEDURE test_maxsum(uid varchar(25))
BEGIN
SET #SQL = CONCAT('SELECT MAX(sum_val) INTO #maxsum FROM ', uid);
PREPARE stmt FROM #SQL;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
SELECT #maxsum;
END//
DELIMITER ;

mysql prepared statment giving error

i am trying to write a stored procedure which updates the field of a table as specified in the argument .i am getting syntax error in #sql statment.please help
create procedure new_upd1(ind int(3),attribute varchar(30),pk int(11),new_value varchar(30))
begin
set #att=attribute;
set #primk=pk;
set #updated=new_value;
if ind=1 then
set #sql='update department set ?=? where departmentid=?';
prepare stmt from #sql;
execute stmt using #att,#updated,#primk;
deallocate prepare stmt;
end if;
end
Parameters don't work for column or table names, only for values. Do it like this:
create procedure new_upd1(ind int(3),attribute varchar(30),pk int(11),new_value varchar(30))
begin
set #att=attribute;
set #primk=pk;
set #updated=new_value;
if ind=1 then
set #sql=CONCAT('update department set ', #att, '=? where departmentid=?;');
prepare stmt from #sql;
execute stmt using #updated,#primk;
deallocate prepare stmt;
end if;
end

How to Use Multiple Parameters in a MySQL *Prepared* Stored Procedure

Although there are some good examples of multiple parameters being used in MySQL stored procedures, I have been unable to find a simple example that shows how to use them in a stored procedure that is prepared.
The code below returns 'Incorrect arguments to EXECUTE' when calling it using: `call test_parms('my report','example.com');
I've tried with and without '#' in front of the parameter names (just gives an unknown column error), and different variations of the code . What am I doing wrong?
DELIMITER $$
DROP PROCEDURE IF EXISTS `test_parms`$$
CREATE DEFINER=`root`#`localhost` PROCEDURE `test_parms`(REPORT VARCHAR(255),DOMAIN_NAME VARCHAR(255))
BEGIN
SET #sql = "Select #DOMAIN_NAME,#REPORT";
set #REPORT=REPORT;
set #DOMAIN_NAME=DOMAIN_NAME;
PREPARE stmt FROM #sql;
EXECUTE stmt using #DOMAIN_NAME,#REPORT;
DEALLOCATE PREPARE stmt;
END$$
DELIMITER ;
The following section of the documentation will be helpful: 13.5.1. PREPARE Syntax.
DELIMITER $$
DROP PROCEDURE IF EXISTS `test_parms`$$
CREATE PROCEDURE `test_parms`(`REPORT` VARCHAR(255), `DOMAIN_NAME` VARCHAR(255))
BEGIN
SET #`sql` := 'SELECT ? `DOMAIN_NAME`, ? `REPORT`';
SET #`REPORT` := `REPORT`;
SET #`DOMAIN_NAME` := `DOMAIN_NAME`;
PREPARE `stmt` FROM #`sql`;
EXECUTE `stmt` USING #`DOMAIN_NAME`, #`REPORT`;
DEALLOCATE PREPARE `stmt`;
END$$
DELIMITER ;
SQL Fiddle demo
UPDATE
DELIMITER $$
DROP PROCEDURE IF EXISTS `test_parms`$$
CREATE PROCEDURE `test_parms`(`REPORT` VARCHAR(255), `DOMAIN_NAME` VARCHAR(255))
BEGIN
SELECT `DOMAIN_NAME` `DOMAIN_NAME`, `REPORT` `REPORT`;
END$$
DELIMITER ;
SQL Fiddle demo
Looks like I was unnecessarily setting user defined variables prior to execution, which was included in some of the stored procedure examples, but apparently doesn't work if the stored procedure is prepared.
To fix, Replace the following code:
set #REPORT=REPORT;
set #DOMAIN_NAME=DOMAIN_NAME;
PREPARE stmt FROM #sql;
EXECUTE stmt using #DOMAIN_NAME,#REPORT;
with this :
PREPARE stmt FROM #sql;
EXECUTE stmt;
So the corrected code looks like:
DELIMITER $$
DROP PROCEDURE IF EXISTS `test_parms`$$
CREATE DEFINER=`root`#`localhost` PROCEDURE `test_parms`(REPORT VARCHAR(255),DOMAIN_NAME VARCHAR(255))
BEGIN
SET #sql = "Select #DOMAIN_NAME,#REPORT";
PREPARE stmt FROM #sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END$$
DELIMITER ;
Update
I ended up with the following which works with any user with privileges to execute procedures ('process' permission is not required like it is for the previous code) and works correctly on SQL Fiddle:
DROP PROCEDURE IF EXISTS `test_parms`//
CREATE PROCEDURE `test_parms`(REPORT VARCHAR(255),DOMAIN_NAME VARCHAR(255))
BEGIN
SET #sql = "Select #DOMAIN_NAME,#REPORT";
SET #DOMAIN_NAME=DOMAIN_NAME;
SET #REPORT=REPORT;
PREPARE stmt FROM #sql;
EXECUTE STMT;
DEALLOCATE PREPARE STMT ;
END//
SQL Fiddle - Updated Final

Dynamic MySQL Procedure not working

Delimiter //
CREATE Procedure SearchTest(IN FieldName varchar(30),IN FieldValue varchar(30))
BEGIN
SET #query = CONCAT('select count(*) from Some_table_name where ', FieldName,'=',FieldValue);
PREPARE stmt FROM #query;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END //
Delimiter ;
mysql> call SearchTest('accession_no','L138362194');
ERROR 1054 (42S22): Unknown column 'L138362194' in 'where clause'
Your database table does not have a column L138362194.
You can fix that by adding such a column, or by choosing a column that exists.
The error is generated because of missing quotes. Here is an SQL Fiddle that demonstrates the problem.
Modify the stored procedure:
DELIMITER //
CREATE PROCEDURE SearchTest(IN FieldName VARCHAR(30), IN FieldValue VARCHAR(30))
BEGIN
SET #query = CONCAT('SELECT COUNT(*) FROM `some_table_name` WHERE ', FieldName, ' = \'', FieldValue, '\';');
PREPARE stmt FROM #query;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END //
DELIMITER ;

Using Prepared statement in Dynamic view

Here is my code
Drop procedure if exists test//
CREATE PROCEDURE test(IN woeid VARCHAR(15))
BEGIN
SET #w1 := woeid;
SET #sql = CONCAT('CREATE OR REPLACE VIEW temp
AS
SELECT *
FROM test_table gp
WHERE gp.name =', #w1);
PREPARE stmt FROM #sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END//
Delimiter ;
call test('ABCD');
I am getting error as
Error code: 1054. Unknown column 'ABCD' in 'where' clause
Please help.
It sounds as though you're needlessly using views, when some other approach would be more appropriate.
However, the reason it isn't working is that you haven't quoted your string literal, so the resulting SQL contains WHERE gp.name = ABCD whereas it at very least needs to be WHERE gp.name = 'ABCD'. You can use MySQL's QUOTE() function for this purpose, but it's better to parameterise the value:
DELIMITER //
DROP PROCEDURE IF EXISTS test//
CREATE PROCEDURE test(IN woeid VARCHAR(15))
BEGIN
SET #w1:=woeid, #sql:=CONCAT('
CREATE OR REPLACE VIEW temp AS
SELECT *
FROM test_table
WHERE name = ?
');
PREPARE stmt FROM #sql;
EXECUTE stmt USING #w1;
DEALLOCATE PREPARE stmt;
SET #w1:=NULL, #sql:=NULL;
END//
DELIMITER ;
CALL test('ABCD');