I am writing a stored procedure in mysql which simply returns the row with ID provided or return all table when no ID is provided.
CREATE DEFINER=`root`#`localhost` PROCEDURE `SLICE_GET`(`slice_id` int)
BEGIN
SELECT *
FROM `thesis_db`.`SLICE_INFO`
WHERE (SLICE_ID = `slice_id` OR `slice_id` IS NULL);
END
I have used the same idea in ms-sql for years yet it doesn't seem to work for mysql since no matter which ID is passed, the procedure returns entire table.
What am I missing here ?
This is a way to write procedures in mysql
DELIMITER $$
CREATE PROCEDURE `name of procedure` (x CHAR(1), D1 DATE, D2 DATE)
BEGIN
SELECT name of columns you want to display
FROM table name
WHERE SLICE_ID= x
OR SLICE_ID IS NULL;
END
$$
Note: Moreover mysql is not case sensitive means all caps or all small will not effect it.
delimiter is used to:
If you use the mysql client program to define a stored program containing semicolon characters, a problem arises.
By default, mysql itself recognizes the semicolon as a statement delimiter, so you must redefine the delimiter temporarily to cause mysql to pass the entire stored program definition to the server.
Related
I'm trying out MySQL procedures for the first time, however I can't figure out how to define the variable #index_ids for the life of me. It really doesn't like the SET.
CREATE PROCEDURE #indextemp
BEGIN
SET #index_ids = (SELECT DISTINCT index_id FROM visibility_index_processing_queue WHERE process_id IS NOT NULL);
SELECT #index_ids;
END
Problem is in CREATE PROCEDURE syntax, not in setting variable. You just have to add parentheses after procedure name. Here's working sample
delimiter $
CREATE PROCEDURE indextemp()
BEGIN
SET #index_ids = (SELECT DISTINCT index_id FROM visibility_index_processing_queue WHERE process_id IS NOT NULL);
SELECT #index_ids;
END$
delimiter ;
Sometimes use of delimiter character in procedure body can cause problems too. That's why I set delimiter to $ before creating procedure and revert it to default ; after I'm done.
Also notice that I have removed # from your procedure name. In sql # is used to insert comments. If for some reason you really want to use it in your name you have to do it like that
CREATE PROCEDURE `#indextemp`()
Is it possible to use a procedure inside a function? For example, I would like to gather all my rows related to an id but I would also like to count the rows and use it in a select statement. This is not working:
drop procedure if exists relatives;
create procedure relatives(in parent int(11),out counted int(11))
begin
set counted=(select count(*) from category where related=parent);
end;
drop function if exists relatives_count;
create function relatives_count(parent parent(11)) returns int(11)
begin
declare count int(11);
call relatives(parent,counted);
return counted;
end;
So that I can use the count
select relatives_count(id) from category
This is just for curiosity purposes. It may look senseless since I can just call a single select query and get the same results but I want to know how I can use my procedure out variable in a function.
Yes, a MySQL FUNCTION can call a MySQL PROCEDURE.
But... the operations the procedure performs will be limited to the operations allowed by a function. (We can't use a procedure to workaround the limitations placed on a function.)
"is not working" is so nebulously vague as to be practically useless in debugging the issue. What exact behavior is being observed?
My suspicion is that the SQL statements shown are failing, because there is no override for the default statement delimiter.
Also, parent(11) is not a valid datatype.
Be aware that when an identifier for a column in a SQL statement in a MySQL stored program matches an identifier used for an argument or local variable, MySQL follows a rule about which (the column name or the variable) that is being referenced.
Best practice is to adopt a naming convention for arguments and local variables that do not match column names, and to qualify all column references with a table name or table alias.
Personally, I use a prefix for arguments and local variables (a for argument, l for local, followed by a datatype i for integer, d for date/datetime, n for decimal, ...
DELIMITER $$
DROP PROCEDURE IF EXISTS relatives$$
CREATE PROCEDURE relatives(IN ai_parent INT(11),OUT ai_counted INT(11))
BEGIN
SELECT COUNT(*)
INTO ai_counted
FROM category c
WHERE c.related = ai_parent
;
END$$
DROP FUNCTION IF EXISTS relatives_count$$
CREATE FUNCTION relatives_count(ai_parent INT(11))
RETURNS INT(11)
BEGIN
DECLARE li_counted INT(11);
CALL relatives(ai_parent,li_counted);
RETURN li_counted;
END$$
DELIMITER ;
Please identify the exact behavior you observe. Error message when creating the procedure? Error message when executing the function? Unexpected behavior. That's much more precise and informative than telling us something "is not working".
I am learning to write MySQL stored procedures and I have encountered some difficulties. Here I have two stored procedures:
First stored procedure:
CREATE PROCEDURE sp1 (IN `username` TEXT, OUT `user_id` INT)
BEGIN
DECLARE rowcount INT;
SELECT count(`User ID`) INTO rowcount FROM user WHERE `Username`=username;
SET user_id = rowcount;
END|
Second stored procedure:
CREATE PROCEDURE sp2 (IN `doc_id` INT, IN `content` LONGTEXT)
BEGIN
UPDATE doc SET `Content`=content WHERE `Doc ID`=doc_id;
END|
(Delimiter is |.)
Question:
I observe that the result of the first stored procedure is the same as calling SELECT count(`User ID`) FROM user;. However, the second stored procedure does its job and gets the content updated with the new content.
So why does the first stored procedure treat `Username` and username as equal identifiers but the second stored procedure treats `Content` and content as different identifiers? The two identifiers in both cases are the same except the capitalization of the first letter.
I figure it out after reading the official MySQL documentation about the scope of local variables.
It states that:
A local variable should not have the same name as a table column. If an SQL statement, such as a SELECT ... INTO statement, contains a reference to a column and a declared local variable with the same name, MySQL currently interprets the reference as the name of a variable.
I'm new to stored procedure and I don't know much.
I'm testing with an example. Could you help me?
Here is my stored procedure
DELIMITER $$
DROP PROCEDURE IF EXISTS dictionarytable$$
CREATE PROCEDURE dictionarytable(id VARCHAR(20),name
VARCHAR(20),work VARCHAR(20),place VARCHAR(20),mobileno
VARCHAR(20),bike VARCHAR(20),car VARCHAR(20),homeno
VARCHAR(20),dictionaytype VARCHAR(20),meaning VARCHAR(20),sentence
VARCHAR(20),antonym VARCHAR(20),synonym VARCHAR(20))
BEGIN
select
id,name,work,place,mobileno,bike,car,homeno,dictionaytype,meaning,sentence,antonym,synonym
from dictionary INTO dictionarytable; END $$
DELIMITER ;
I wanted id,name,13 columns from dictionary(table) to be called in stored procedure dictionarytable
the query in the Begin is wrong could you specify a query to display all 13 columns
You cannot pass field values INTO the procedure, you can pass them INTO user variables, declared variables or OUT paramaters. Note, that only one record can be passed when INTO clause is used. For example:
SET #var1 = NULL;
SELECT column1 INTO #var1 FROM table;
If you want to copy more then one record, then you can use INSERT INTO...SELECT statement to copy data-set to second table. For example:
INSERT INTO table2 SELECT column1 FROM table;
Also, if you want to use variables or parameters as identifiers (field names in your case), then you should use prepared statements.
I am using DBVisualizer for the first time. I have made a stored procedure in mysql database. However I am unable to execute it from DBVisualizer.
This is how the procedure looks like. Here // is used as delimiter. I have four columns in the table namely slno int (autoincrement), time timestamp, price int, and prodid varchar.
*DROP PROCEDURE `spTest`//
CREATE DEFINER=`root`#`localhost` PROCEDURE `spTest`()
BEGIN
SELECT * FROM dummy1 where prodid=pr01;
END*
In DBVisualizer, I am executing #call spTest()
Where am I going wrong?
As the definer of the stored procedure is root, your DBVizualizer connection to MySQL must be as the root user in order to execute it.