Is it possible to pass input parameter into Cursor SELECT statement WHERE clause?
For some reason I think it isn't working.
I'm trying to pass _TAG and _ITEM_NAME into where clause.
DECLARE cursor_test cursor for SELECT itemid FROM items WHERE key_ LIKE "sometext_#_TAG_sometext_#_ITEM_NAME" AND STATUS = '0';
Here is the the Stored procedure:
DELIMITER //
CREATE PROCEDURE getSomething(IN _HOSTNAME VARCHAR(20), _TAG VARCHAR(20), _ITEM_NAME VARCHAR(50))
BEGIN
declare FINISHED BOOL default false;
DECLARE cursor_test cursor for SELECT itemid FROM items WHERE hostid = #_HOSTID AND key_ LIKE "sometext_#_TAG_sometext_#_ITEM_NAME" AND STATUS = '0';
DECLARE CONTINUE HANDLER for not found set FINISHED := true;
SET #HOSTNAME = _HOSTNAME;
PREPARE STMT1 FROM
"SELECT hostid INTO #_HOSTID FROM hosts WHERE NAME = ?";
EXECUTE STMT1 USING #HOSTNAME;
DEALLOCATE PREPARE STMT1;
open cursor_test;
SET #TOTAL_VALUE := 0;
loop_itemid: loop
fetch cursor_test into _ITEMID;
SELECT _ITEMID;
if FINISHED then
leave loop_itemid;
end if;
SET #TOTAL_VALUE := #TOTAL_VALUE + (SELECT value from history_uint WHERE itemid = _ITEMID ORDER BY clock DESC LIMIT 1);
end loop loop_itemid;
SELECT #TOTAL_VALUE;
close cursor_test;
END //
Thanks to akina's comment. Using CONCAT in where condition worked.
WHERE key_ LIKE CONCAT('sometext_', _TAG, '_sometext_', _ITEM_NAME)
I'm trying the stored procedure below. However, when i pass the actual column name in 'DECLARE cur1' line, the SP returns correct value but when I pass variable name i.e. input parameter (colName), it returns 0. I've added comments in my code below. Is the code correct?
DROP PROCEDURE IF EXISTS test1.checkHardcodedField;
CREATE PROCEDURE test1.checkHardcodedField(IN textValue CHAR(10), colName CHAR(10), OUT counter VARCHAR(100))
BEGIN
DECLARE done INT DEFAULT FALSE;
DECLARE temp CHAR(16);
DECLARE i INT DEFAULT 0;
-- Issue with this statement, returns incorrect value.
DECLARE cur1 CURSOR FOR SELECT colName FROM data1;
-- This statement works. MSH3 is actual column name
-- DECLARE cur1 CURSOR FOR SELECT MSH3 FROM data1;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
OPEN cur1;
read_loop: LOOP
FETCH cur1 INTO temp;
IF done THEN
LEAVE read_loop;
END IF;
IF temp = textValue THEN
SET i = i + 1;
END IF;
END LOOP;
SET counter = i;
CLOSE cur1;
END;
CREATE PROCEDURE procedure_name (..., fieldname VARCHAR, ...)
BEGIN
CREATE TEMPORARY TABLE tmp (field VARCHAR(10));
SET #sql := CONCAT('INSERT INTO tmp SELECT ', fieldname, ' FROM tablename;');
PREPARE stmt FROM #sql;
EXECUTE stmt;
DROP PREPARE stmt;
BEGIN
DECLARE cur CURSOR FOR SELECT field FROM tmp;
...
END;
DROP TABLE tmp;
END
I put the cursor declaration in the prepared statement and then executed it, then returns an error #1324 - Undefined CURSOR: getid.
How do I solve this problem?
delimiter ;;
drop procedure if exists test2;;
create procedure test2(table_id VARCHAR(25))
BEGIN
DECLARE done INT DEFAULT FALSE;
DECLARE id INT;
DECLARE id_new INT;
DECLARE stmt1 VARCHAR(1024);
DECLARE stmt2 VARCHAR(1024);
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
SET #sqltext1 := CONCAT('DECLARE getid CURSOR FOR SELECT entryId FROM ',table_id,' ORDER BY entryId');
PREPARE stmt1 FROM #sqltext1;
EXECUTE stmt1;
SET #id_new = 1;
OPEN getid;
FETCH getid into id;
REPEAT
SET #sqltext2 := CONCAT('UPDATE ',table_id,' SET entryId = ? WHERE entryId = ?');
PREPARE stmt2 FROM #sqltext2;
EXECUTE stmt2 USING #new_id, id;
SET #id_new = #id_new + 1;
FETCH getid into id;
UNTIL done END REPEAT;
CLOSE getid;
END
;;
CALL test2('Test');
Some rules:
All declarations must be at one place in a sequence.
You can't use variable names in cursor declarations.
Handler declarations must be after cursor declarations.
You can't use local variable names (id) as bound parameters for
prepared statements. You can only use session variables (say #_id).
To overcome such problems, you can adopt following solution.
Define a temporary table using the input parameter to the SP.
Now declare the cursor on the same table and use it.
Drop the temporary table created.
Following example should work on your tables.
delimiter $$
drop procedure if exists test2$$
create procedure test2( table_id varchar(25) )
begin
set #temp_query = 'drop temporary table if exists temp_cursor_table';
prepare pst from #temp_query;
execute pst;
drop prepare pst; -- or
-- deallocate prepare pst;
set #temp_table_query='create temporary table temp_cursor_table ';
set #temp_table_query=concat( #temp_table_query, ' select entryId from ' );
set #temp_table_query=concat( #temp_table_query, table_id );
set #temp_table_query=concat( #temp_table_query, ' order by entryId' );
prepare pst from #temp_table_query;
execute pst;
drop prepare pst;
-- now write your actual cursor and update statements
-- in a separate block
begin
declare done int default false;
declare id int;
declare id_new int;
declare stmt1 varchar(1024);
declare stmt2 varchar(1024);
declare getid cursor for
select entryId from temp_cursor_table order by entryId;
declare continue handler for not found set done = 1;
set #id_new = 1;
open getid;
fetch getid into id;
repeat
set #sqltext2 := concat( 'update ', table_id );
set #sqltext2 := concat( #sqltext2, ' set entryId = ? where entryId = ?' );
set #_id = id;
prepare stmt2 from #sqltext2;
execute stmt2 using #new_id, #_id;
set #id_new = #id_new + 1;
fetch getid into id;
until done end repeat;
close getid;
end;
end;
$$
delimiter ;
Now call the procedure with table_id value.
call test2( 'Test' );
I wrote this function:
delimiter //
CREATE FUNCTION randomDefVal(val varchar(30), tableName varchar(30))
returns varchar(30)
BEGIN
SET #query = concat('SELECT ',val,' FROM ',tableName,' ORDER BY rand() LIMIT 1;');
SET #result = NULL;
PREPARE stmt1 FROM #query;
return (EXECUTE stmt1);
END//
But I have an error in the last line:
SQL Error (1336): Dynamic SQL is not allowed in stored function or trigger
Which suggests that I cannot write 'return (EXECUTE stmt1);'
How can I return the value, which will be the result of the 'EXECUTE' statement?
I think what you want is SELECT ... INTO. So you would have something like this within your BEGIN and END (note that I have not tested this code):
BEGIN
DECLARE var_name VARCHAR(30);
SET var_name = '';
SELECT val INTO var_name FROM tableName ORDER BY rand() LIMIT 1;
RETURN var_name;
END
I have two inputs for my stored procedure. One is the 'RoledID' and second one is the 'MenuIDs'. 'MenusIDs' is a list of comma separated menus ids that need to be inserted with RoledID. RoleId is just an INT and we need to put this RoledID against each MenuID. My table 'RolesMenus' contains two columns one for MenuID and one for RoleID.
Now I need to split MenuIDs and insert each MenuID with RoleID.
How can I write a stored procedure for it?
You can build one INSERT query (because statement allows to insert multiple records) and run it with prepared statements, e.g. -
SET #MenuIDs = '1,2,3';
SET #RoledID = 100;
SET #values = REPLACE(#MenuIDs, ',', CONCAT(', ', #RoledID, '),('));
SET #values = CONCAT('(', #values, ', ', #RoledID, ')'); -- This produces a string like this -> (1, 100),(2, 100),(3, 100)
SET #insert = CONCAT('INSERT INTO RolesMenus VALUES', #values); -- Build INSERT statement like this -> INSERT INTO RolesMenus VALUES(1, 100),(2, 100),(3, 100)
-- Execute INSERT statement
PREPARE stmt FROM #insert;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
As you see, it can be done without stored procedure.
Give this a go. It may need some tweaking if the MenuIDs string does not conform to 'menuId,menuId,menuId'.
Also I do not know what data type the menuId column is in your target table (INT?) so you may have to put some numeric checking in too (in case '1,2,3,banana,4,5' is passed in as the MenuIds input parameter).
DELIMITER $$
DROP PROCEDURE IF EXISTS `insert_role_menuids`$$
CREATE PROCEDURE `insert_role_menuids`(IN RoleID INT,IN MenuIDs varchar(500))
BEGIN
declare idx,prev_idx int;
declare v_id varchar(10);
set idx := locate(',',MenuIDs,1);
set prev_idx := 1;
WHILE idx > 0 DO
set v_id := substr(MenuIDs,prev_idx,idx-prev_idx);
insert into RolesMenus (RoleId,MenuId) values (RoleID,v_id);
set prev_idx := idx+1;
set idx := locate(',',MenuIDs,prev_idx);
END WHILE;
set v_id := substr(MenuIDs,prev_idx);
insert into RolesMenus (RoleId,MenuId) values (RoleID,v_id);
END$$
DELIMITER ;
for this solution, you must create a table with the name split_table, it can have a id(autoincrement) if you need it and must have a column where to store the value (I call it valor)
DELIMITER $$
USE `dbaname`$$
DROP PROCEDURE IF EXISTS `Split`$$
CREATE DEFINER=`root`#`localhost` PROCEDURE `Split`(
IN cadena VARCHAR(8000),
IN delimitador VARCHAR(10)
)
BEGIN
TRUNCATE split_table;
SET #posicion = 1;
SET #ldel = LENGTH(delimitador);
SET #valor = SUBSTRING_INDEX(cadena, delimitador, 1);
WHILE #valor <> '' AND #posicion > 0 DO
SET #valor = SUBSTRING_INDEX(cadena, delimitador, 1);
INSERT INTO split_table(valor) VALUES (#valor);
SET #posicion = POSITION(delimitador IN cadena);
SET #largo = LENGTH(cadena);
IF #largo >= #posicion THEN
SET cadena = SUBSTR(cadena, #posicion + #ldel, #largo - #posicion);
SET #valor = SUBSTRING_INDEX(cadena, delimitador, 1);
ELSE
SET #posicion = 0;
END IF;
END WHILE;
END$$
DELIMITER ;
First create procedure
CREATE DEFINER=`root`#`localhost` PROCEDURE `split_str_save_to_tmp_table`(
IN _str TEXT,
IN _table_name VARCHAR(80)
)
BEGIN
#DROP FIRST OLD TABLE
SET #q = CONCAT('DROP TEMPORARY TABLE IF EXISTS ', _table_name);
PREPARE st FROM #q;
EXECUTE st;
#CREATE TABLE
SET #q = CONCAT('CREATE TEMPORARY TABLE ', _table_name, '(id INT UNSIGNED NOT NULL PRIMARY KEY (id) )' );
PREPARE st FROM #q;
EXECUTE st;
SET #ids = REPLACE(_str, ',', '),(');
SET #ids = CONCAT('(', #ids, ')');
#INSERT INTO TABLE
SET #q = CONCAT('INSERT INTO ' , _table_name ,' VALUES');
SET #q = CONCAT(#q, #ids);
PREPARE st FROM #q;
EXECUTE st;
DEALLOCATE PREPARE st;
END
Then call
call split_str_save_to_tmp_table('1,2,3,4,5', 'tmp_split_product');
SELECT * FROM tmp_split_product
AFAIK MySQL does not have a function to split strings. Here is the MySQL manual for string related functions. In the comments section should be some information about workarounds for splitting string with substring-functions but not really usable:
MySQL manual