I am trying to execute a stored procedure on a range of records from nth to nth. How can I write the code to get my desired results?
This code output values for whole number of rows but I want results from rows between 100 to 300 OR 500 to 600 based on same conditions as written in code. I am working on SQL Server 2008
USE GERP
DECLARE #ProductID NVARCHAR(50)
DECLARE cur CURSOR LOCAL FOR
SELECT ProductID
FROM STK_ProductMaster
WHERE ParentPCode LIKE '3%' AND Status = 'Active'
OPEN cur
FETCH NEXT FROM cur INTO #ProductID
WHILE ##FETCH_STATUS = 0
BEGIN
EXEC sp_GetBOMCost #ProductID
FETCH NEXT FROM cur INTO #ProductID
END
CLOSE cur
DEALLOCATE cur
Related
Mysql (version 5.7) cursor not working. I tried many times and checked online could not find what is wrong.
It is looping through correctly as many records in the currency table. But when I try to read from the cursor it is only returning null and not the actual values from the table currency. The currency table has data.
DROP PROCEDURE IF EXISTS proc2;
CREATE PROCEDURE proc2()
BEGIN
DECLARE finished INTEGER DEFAULT 0;
DECLARE code VARCHAR(255);
DECLARE myCursor CURSOR FOR SELECT code FROM currency;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET finished = 1;
OPEN myCursor;
delete from dummy;
read_loop: LOOP
FETCH myCursor INTO code;
IF finished = 1 THEN
LEAVE read_loop;
END IF;
insert into dummy(name) values(code);
END LOOP read_loop;
CLOSE myCursor;
End;
At last, it worked with below change to the script. (i.e. after adding table alias.)
For some reason, the column I tried out 'code' expects an alias. Maybe a reserved keyword, not sure.
DECLARE myCursor CURSOR FOR SELECT c.code FROM currency c;
Data fetched from cursor is NULL. But number of row my query select id from Projects returning is correct. I have put a select statement in my procedure loop to debug. It's returning null for id.
I have followed this [https://dev.mysql.com/doc/refman/5.5/en/cursors.html]
What's wrong with this code?
DELIMITER $$
CREATE DEFINER=`root`#`localhost` PROCEDURE `ReportDiffProDiffFinYear`()
BEGIN
DECLARE id INT;
DECLARE sqlstr varchar(10000) default "select financialYear as 'name' ";
DECLARE done INT DEFAULT FALSE;
DECLARE cur1 CURSOR FOR select id from Projects; /* My CURSOR QUERY*/
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
OPEN cur1;
read_loop: LOOP
FETCH cur1 INTO id;
select id;
IF done THEN
LEAVE read_loop;
END IF;
set sqlstr = concat(sqlstr, ", sum(if(projects_id=",id,",0,1)) ");
END LOOP;
CLOSE cur1;
set #sqlstr = concat(sqlstr," from (select * from WaterPoints where status='Waterpoint Complete') as wp, (select id,financialYear from ProjectDetails) as pd where pd.id=wp.projectDetails_id group by pd.financialYear");
prepare stmt from #sqlstr;
execute stmt;
deallocate prepare stmt;
END
I believe that your variable name id clashes with the query for the cursor, therefore the cursor query fetches the value of the id variable (null), not the value of the id from the projects table. Either change the name of the variable or use projects.id to reference the column in the query.
I try to create a stored procedure in phpmyadmin, but I get a error 1064 on line 12 (where the WHILE is). This is the first time I try to create a stored procedure.
BEGIN
DECLARE product_id INT;
DECLARE product_min_age nvarchar(500);
DECLARE cur CURSOR for
SELECT product_min_age, product_id FROM _vm_product;
open cur;
fetch next from cur into product_min_age, product_id;
while FETCH_STATUS = 0 BEGIN
INSERT INTO _virtuemart_product_customfields (virtuemart_product_id, virtuemart_custom_id, customfield_value, customfield_params) VALUES
( product_id, 5, product_min_age, 'addEmpty=0|selectType=0|');
fetch next from cur into product_min_age,product_id;
END;
close cur;
END
Thank you
You should change that to below. See Documentation for more information.
open cur;
read_loop: LOOP
fetch cur into product_min_age, product_id;
INSERT INTO _virtuemart_product_customfields (virtuemart_product_id, virtuemart_custom_id, customfield_value, customfield_params) VALUES
( product_id, 5, product_min_age, 'addEmpty=0|selectType=0|');
END LOOP;
close cur;
The accepted answer is indeed correct and so is your own answer. Unfortunately the approach is completely wrong!
One does not generally perform sql queries inside a loop unless as a last resort. Select / loop / insert is in fact a frequent pattern followed by people writing their first stored procedure. but there is a better way, a much much better way. And that is INSERT .. SELECT
With INSERT ... SELECT, you can quickly insert many rows into a table
from one or many tables. For example:
Your complex stored procedure reduces to:
INSERT INTO _virtuemart_product_customfields (virtuemart_product_id, virtuemart_custom_id, customfield_value, customfield_params)
SELECT product_id, 5, product_min_age, 'addEmpty=0|selectType=0|'
FROM _vm_product
That's it, just a simple select, no stored procedures!
A second issue is that you are stored delimited text in a column.
addEmpty=0|selectType=0|
I am not quite sure why you are doing this but it's most unusual.
If someone want to see my final result:
BEGIN
DECLARE _product_id INT;
DECLARE _product_min_age nvarchar(500);
DECLARE done INT DEFAULT 0;
DECLARE cur CURSOR for SELECT product_min_age, product_id FROM _vm_product;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
open cur;
read_loop: LOOP
fetch cur into _product_min_age, _product_id;
IF done = 1 THEN
LEAVE read_loop;
END IF;
INSERT INTO _virtuemart_product_customfields (virtuemart_product_id, virtuemart_custom_id, customfield_value, customfield_params) VALUES
( _product_id, 5, _product_min_age, 'addEmpty=0|selectType=0|');
END LOOP;
close cur;
END
I am working on a MySQL procedure that creates a summary of one of my tables. The procedure retrieves a dataset and loops through it using a cursor. For each iteration of the loop, the procedure updates another table. The problem I'm having is the loop ends after a single iteration, event though I know that the query I'm running retrieves more than one row.
BEGIN
# Variable declaration section omitted for brevity
DECLARE cur CURSOR FOR SELECT
t.result_id,
t.athlete_id, t.`first`, t.middle, `last`, t.pref, t.birth,t.uss,
t.club_id,t.code,t.club_name,
t.meet_name,t.meet_id,t.`start`,t.`end`,
MIN(t.time) as time,t.age,t.type
FROM sometable t GROUP BY club_id ORDER BY time asc,t.start desc,club_id;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN cur;
read_loop: LOOP
FETCH cur INTO result_id,athlete_id, first_name, middle, last_name, pref, birth,uss,
club_id,club_code,club_name,
meet_name,meet_id,start_date,end_date,
result_time,age,type;
IF done=1 THEN
LEAVE read_loop;
END IF;
SET last_time = result_time;
INSERT INTO toptimes(`result_id`,`club_id`,`agegroup`,`sex`,`distance`,`course`,`stroke`,`data`,`published`)
VALUES(result_id,club_id,AgeGroupID,sex,distance,course,stroke,json,0);
END LOOP read_loop;
CLOSE cur;
END
I'm not clear what the problem is. When I run the select query manually, I get back several rows. Is there a problem running an insert statement inside the loop?
Your code chunk looks good to me.
How do you know that it's running only one iteration (i'm not seeing any
print or select statement for debug purpose)?
Are you getting any error while executing the stored procedure?
I tried to replicate the similar code with "sakila" database (mysql sample db). It's working perfectly. Please check this sql code sample, if it helps you.
DROP PROCEDURE IF EXISTS usp_select_dummy_data ;
DELIMITER $$
CREATE DEFINER=`root`#`localhost` PROCEDURE usp_select_dummy_data()
BEGIN
-- Declare your variables
Declare _var_actor_id int default 0;
DECLARE _var_film_id int default 0;
-- Declare variable used for cursor and loop control
DECLARE done int;
DECLARE loop_counter INT DEFAULT 0;
-- Declare the cursor
DECLARE cur CURSOR FOR
SELECT
actor_id, film_id
FROM film_actor;
-- Declare handlers
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
-- Open the cursor
OPEN cur ;
-- Start the loop
read_loop: LOOP
FETCH cur
INTO _var_actor_id, _var_film_id ;
-- break out of the loop if
-- 1. if there is no rows or
-- 2. we've processed them all
IF done = 1 THEN
CLOSE cur ;
LEAVE read_loop ;
END IF;
-- Count the number of times looped
SET loop_counter = loop_counter + 1 ;
END LOOP read_loop ;
-- print the loop count
select loop_counter;
END
I am making a stored procedure in order to check that whether a user exists or not. The problem is whenever I pass it the correct username, it executes successfully but when I pass wrong username, it go through an infinite loop.
Where am I going wrong? Here is my Stored Procedure:
CREATE PROCEDURE `VerifyUserNPass`(userParam varchar(50), out result int)
BEGIN
DECLARE done INT DEFAULT FALSE;
DECLARE tempUser varchar(50) default '';
DECLARE count int default 0;
DECLARE noRows int;
DECLARE userList cursor for select userName from users;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
select count(*) into noRows from users;
OPEN userList;
read_loop: LOOP
FETCH userList into tempUser;
IF tempUser = userParam THEN
SET #count = count + 1;
LEAVE read_loop;
ELSEIF count > noRows THEN
LEAVE read_loop;
END IF;
END LOOP;
CLOSE userList;
select count into result;
END
To fix your code, use a conditional test on the done variable to determine whether to leave the loop. (The done variable is initialized to FALSE, and then set to TRUE in the CONTINUE HANDLER when there are no more rows.)
Get rid of the query "count(*)" query, and the noRows variable; those are not needed. (In a concurrent system, it's possible for that count(*) query to return a value that differs from the number of rows returned by a later query. (Consider that its possible for other sessions to insert or delete rows while your procedure is running.)
Also get rid of the references to the #count user variable. You have a mixture of references, to both a user variable #coount and a procedure variable count. These are independent variables. There's no need for your procedure to use a user variable. Instead, stick with using variables that are declared in your procedure. (Save the user variables for when you have a need.)
-- select count(*) into noRows from users;
read_loop: LOOP
FETCH userList into tempUser;
IF done THEN
LEAVE read_loop;
END IF;
IF tempUser = userParam THEN
SET count = 1;
LEAVE read_loop;
END IF;
END LOOP;
A more efficient way to code this would be to let the database find the row(s) you are interested in, by adding a WHERE clause on your query. (There's no need for you to fetch rows that aren't going to match the condition you are interested in.)
Modify your cursor definition to include a predicate (i.e. a condition in a WHERE clause) to limit the rows returned:
DECLARE userList cursor for select userName from users
WHERE userName = userParam LIMIT 1;
I don't understand the need for a procedure here. A native SQL statement would be much more efficient, e.g.
SELECT 1 AS found FROM users u WHERE u.userName = 'foo' LIMIT 1;
Make sure you increment your loop counter for all branches not only in the succes branch and have result variable to hold your outcome.
DECLARE userFound int default 0;
......
read_loop: LOOP
FETCH userList into tempUser;
SET #count = #count + 1;
IF tempUser = userParam THEN
SET #userFound = 1
LEAVE read_loop;
ELSEIF count > noRows THEN
LEAVE read_loop;
END IF;
.....
select userFound into result;
And I would expect that this would return the same result (but I'm not an MySql expert)
CREATE PROCEDURE `VerifyUserNPass`(userParam varchar(50), out result int)
BEGIN
select COUNT(userName) into result from users where username = #userParam
END