I have the following stored procedure:
DELIMITER ///
CREATE PROCEDURE tmp_test_proc(__TABLE__NAME varchar(255))
BEGIN
SELECT COUNT(*) FROM __TABLE__NAME;
END///
DELIMITER ;
I would like to select from the parameter __TABLE__NAME, but MySQL tells me there is no table __TABLE__NAME... So is there a way to use the value of the parameter in the from clause?
you cannot parameterized table names (as well as column names) by default, you need to create PreparedStatement for this,
DELIMITER ///
CREATE PROCEDURE tmp_test_proc(__TABLE__NAME varchar(255))
BEGIN
SET #sql = CONCAT('SELECT COUNT(*) FROM ', __TABLE__NAME);
PREPARE stmt FROM #sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END///
DELIMITER ;
Related
delimiter //
DROP PROCEDURE IF EXISTS drop_table//
create procedure drop_table(in table_name varchar) #创建带参数的存储过程
begin
drop table if EXISTS table_name;
end//
delimiter ;
call drop_table('a')
i use Navicat to create a procedure to drop a parameter table in mysql.
Error:Invalid Stored Procedure Syntax
As commented by P.Salmon, you cannot pass substitute the procedure argument (ie a variable) directly in a sql statement. You need dynamic sql: build the query as a string, then execute it.
delimiter //
create procedure drop_table(in p_table_name varchar(200))
begin
set #q = concat('drop table if exists ', p_table_name);
prepare stmt from #q;
execute stmt;
deallocate prepare stmt;
end//
delimiter ;
Demo on DB Fiddle
Note: the varchar datatype needs a length.
how to pass varchar string to stored procedure where in condition?
here, where in condition not work how to solve this problem?
CALL searchStudentByName("%AAP%","'1','2','3'");
MYSQL Stored Procedures:
DELIMITER $$
USE `studentsdb`$$
DROP PROCEDURE IF EXISTS `searchStudentByName`$$
CREATE DEFINER=`root`#`localhost` PROCEDURE `searchStudentByName`(IN `search_key` VARCHAR(40),IN `student_ids` VARCHAR(350))
BEGIN
SELECT students.StudentId,students.StudentName FROM students WHERE students.Status='A' AND students.StudentName LIKE search_key AND students.StudentId NOT IN(student_ids) LIMIT 5;
END$$
DELIMITER ;
You really need to prepare a statement to use a list of values like that. Try this:
CREATE DEFINER=`root`#`localhost` PROCEDURE `searchStudentByName`(IN `search_key` VARCHAR(40),IN `student_ids` VARCHAR(350))
BEGIN
SET #sql = CONCAT("SELECT students.StudentId,students.StudentName FROM students WHERE students.Status='A' AND students.StudentName LIKE '", search_key, "' AND students.StudentId NOT IN(", student_ids, ") LIMIT 5");
PREPARE stmt FROM #sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END$$
I'm learning Functions, Procedures and Triggers and I wanted to do a easy procedure that count the rows in a table from parameters.
create procedure countRows(IN v varchar(30))
SELECT COUNT(*) FROM v;
Can someone tell me why if I do:
call countRows('sometable');
call countRows(sometable); //I tried both
It just don't work
Sorry for that newbie question.
You need dynamic sql.
Solution for returning count of any table passed as a parameter to sp
DELIMITER $$
CREATE PROCEDURE `countRows`(IN v varchar(30))
BEGIN
SET #t1 =CONCAT("SELECT COUNT(*) FROM ",V);
PREPARE stmt3 FROM #t1;
EXECUTE stmt3;
DEALLOCATE PREPARE stmt3;
END$$
DELIMITER ;
Execution
call countRows('sometable');
Update: Solution for returning "Table x contain n row(s)" for a table passed as a parameter to sp
DELIMITER $$
CREATE PROCEDURE `countRowsEx`(IN v VARCHAR(30))
BEGIN
-- SET #t1 =CONCAT("SELECT COUNT(*) FROM ",V);
SET #t1 =CONCAT('SET #totalRows=(SELECT COUNT(*) FROM ',v, ' );');
PREPARE stmt3 FROM #t1;
EXECUTE stmt3;
DEALLOCATE PREPARE stmt3;
SELECT CONCAT( 'Table ', v, ' contains ', #totalRows, ' row', IF(#totalRows>1, 's',''));
END$$
DELIMITER ;
Execution
call countRowsEx('sometable');
You can use information_schema for this.
for example to find rows count for table with name stored in variable v use this:
select table_rows from information_schema.tables where table_name = v;
Try this:
call countRows('v');
Although there are some good examples of multiple parameters being used in MySQL stored procedures, I have been unable to find a simple example that shows how to use them in a stored procedure that is prepared.
The code below returns 'Incorrect arguments to EXECUTE' when calling it using: `call test_parms('my report','example.com');
I've tried with and without '#' in front of the parameter names (just gives an unknown column error), and different variations of the code . What am I doing wrong?
DELIMITER $$
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
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');