How do analyse and use EXPLAIN for my stored procedure calls ?
I need to optimize the query time, however seems like there is no where i can do a EXPLAIN call proc_name() ?
You can try
set profiling=1;
call proc_name();
show profiles;
at present you can't explain stored procedures in mysql - but you could do something like this:
drop procedure if exists get_user;
delimiter #
create procedure get_user
(
in p_user_id int unsigned,
in p_explain tinyint unsigned
)
begin
if (p_explain) then
explain select * from users where user_id = p_user_id;
end if;
select * from users where user_id = p_user_id;
end#
delimiter ;
call get_user(1,1);
EXPLAIN works only on SELECT statements, except when you use EXPLAIN tablename which is an alias of DESCRIBE tablename
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`()
I am creating a very simple store procedure with a query, but when i use the store procedure IN parameter in the query it gets stuck and does not execute the query, but if i put the value direct to the query it works.
This works:
CREATE PROCEDURE `cap-reports`.ffap_test()
BEGIN
select * FROM students WHERE name='Fernando';
END
This does not, i spent 10 minutes and it never returned
CREATE PROCEDURE `cap-reports`.ffap_test(IN pName VARCHAR(10))
BEGIN
select * FROM students WHERE name=pName;
END
call `cap-reports`.ffap_test('Fernando');
What mistake i am doing here? I never had this problem before
This procedure works for me. Maybe it's the difference in database of the procedure and the students table? Or a missing semi-colon?
CREATE PROCEDURE `cap-reports`.ffap_test(IN pName VARCHAR(10))
BEGIN
select * FROM `cap-reports`.members m WHERE m.Username = pName;
END
;
CALL `cap-reports`.ffap_test('winkbrace');
DELIMITER $
DROP PROCEDURE IF EXISTS CREATE_BACKUP$
CREATE PROCEDURE CREATE_BACKUP()
BEGIN
DECLARE BACK INT DEFAULT 0;
SELECT TABLE_NAME
FROM information_schema.TABLES
WHERE TABLE_SCHEMA = 'STUDENTDB'
;
SHOW_LOOP:LOOP
IF BACK = 1
THEN
LEAVE SHOW_LOOP;
END IF;
CREATE TABLE STUDENT_BACKUP
AS SELECT * FROM STUDENT;
CREATE TABLE SCORE_BACKUP
AS SELECT * FROM SCORE;
CREATE TABLE GRADE_EVENT_BACKUP
AS SELECT * FROM grade_event;
END LOOP SHOW_LOOP;
END$
DELIMITER ;
Hi, when I run this procedure, it runs more than one time. So I get an error which says "STUDENT_BACKUP table already exists" for the second time when it runs. What should I do to run it just 1 time?
In MySQL you can use CREATE TABLE IF NOT EXIST... to avoid the error occurrence. See CREATE TABLE syntax for details.
To solve your quesrion for SQL server use an INFORMATION_SCHEMA view. A similar solution is in the existing topic.
A similar question about sql-server has been asked here. I'm wondering if its possible in MySql.
edit:
I want to use result set returned from procedure in view.
If you want to get result-set and use routine in FROM clause - NO. Stored routines (procedures or functions) in MySQL cannot return tables as result value.
But you can use functions as simple values, for example -
DELIMITER $$
CREATE FUNCTION mul10(Param1 INT)
RETURNS INT(11)
BEGIN
RETURN Param1 * 10;
END
$$
DELIMITER ;
CREATE OR REPLACE VIEW view1
AS
SELECT mul10(2) AS column1;
SELECT column1 FROM view1;
----------
20
The following procedure gives me an error when I invoke it using the CALL statement:
CREATE DEFINER=`user`#`localhost` PROCEDURE `emp_performance`(id VARCHAR(10))
BEGIN
DROP TEMPORARY TABLE IF EXISTS performance;
CREATE TEMPORARY TABLE performance AS
SELECT time_in, time_out, day FROM attendance WHERE employee_id = id;
END
The error says "Unknown table 'performance' ".
This is my first time actually using stored procedures and I got my sources from Google. I just cant figure out what I am doing wrong.
I've tidied it up a little for you and added example code. I always keep my parameter names the same as the fields they represent but prefix with p_ which prevents issues. I do the same with variables declared in the sproc body but prefix with v_.
You can find another one of my examples here:
Generating Depth based tree from Hierarchical Data in MySQL (no CTEs)
drop procedure if exists emp_performance;
delimiter #
create procedure emp_performance
(
in p_employee_id varchar(10)
)
begin
declare v_counter int unsigned default 0;
create temporary table tmp engine=memory select time_in, time_out
from attendance where employee_id = p_employee_id;
-- do stuff with tmp...
select count(*) into v_counter from tmp;
-- output and cleanup
select * from tmp order by time_in;
drop temporary table if exists tmp;
end#
delimiter ;
call emp_performance('E123456789');
By default MySQL config variable sql_notes is set to 1.
That means that
DROP TEMPORARY TABLE IF EXISTS performance;
increments warning_count by one and you get a warning when a stored procedure finishes.
You can set sql_notes variable to 0 in my.cnf or rewrite stored procedure like that:
CREATE DEFINER=`user`#`localhost` PROCEDURE `emp_performance`(id VARCHAR(10))
BEGIN
SET ##session.sql_notes = 0;
DROP TEMPORARY TABLE IF EXISTS performance;
CREATE TEMPORARY TABLE performance AS
SELECT time_in, time_out, day FROM attendance WHERE employee_id = id;
SET ##session.sql_notes = 1;
END