I have a stored procedure that splits a string and ends with a select.
I would like to run an insert on the stored procedure like you would do an insert on a select
Something like this
INSERT INTO ....
CALL sp_split...
My split looks like this:
DELIMITER $$
CREATE DEFINER=`root`#`localhost` PROCEDURE `split_with_id`(id INT, input varchar(1000), delim VARCHAR(10))
BEGIN
declare foundPos tinyint unsigned;
declare tmpTxt varchar(1000);
declare delimLen tinyint unsigned;
declare element varchar(1000);
drop temporary table if exists tmpValues;
create temporary table tmpValues
(
`id` int not null default 0,
`values` varchar(1000) not null default ''
) engine = memory;
set delimLen = length(delim);
set tmpTxt = input;
set foundPos = instr(tmpTxt,delim);
while foundPos <> 0 do
set element = substring(tmpTxt, 1, foundPos-1);
set tmpTxt = replace(tmpTxt, concat(element,delim), '');
insert into tmpValues (`id`, `values`) values (id, element);
set foundPos = instr(tmpTxt,delim);
end while;
if tmpTxt <> '' then
insert into tmpValues (`id`, `values`) values (id, tmpTxt);
end if;
select * from tmpValues;
END
Create a wrapper function and have it call the procedure. Then SELECT it normally.
DELIMITER $$
CREATE FUNCTION `f_wrapper_split` (strin VARCHAR(255))
RETURNS VARCHAR(255)
BEGIN
DECLARE r VARCHAR(255);
CALL sp_split(strin);
RETURN r;
END
$$
Of course, if sp_split returns multiple results, you'll need to adapt the function to, perhaps, take an INT input as well and return you that particular result. Then just call it multiple times.
It's not very pretty, but that's the best I can think of offhand.
Related
To not publicly disclose our amount of invoices, we want to add random value between 2 ids.
Instead of [1,2,3] we want something like [69,98,179]
UUID is not an option in that project, unfortunately.
Using Mysql 5.7, 8, or MariaDb get the same results.
Here is the approach is taken:
Consider a simple table invoices as follows:
CREATE TABLE `invoices` (
`id` bigint(20) NOT NULL,
`name` varchar(255) DEFAULT NULL,
`created_at` datetime NOT NULL,
`updated_at` datetime NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=42 DEFAULT CHARSET=utf8mb4;
The function to get random values:
DROP FUNCTION IF EXISTS random_integer;
CREATE FUNCTION random_integer(value_minimum INT, value_maximum INT)
RETURNS INT
LANGUAGE SQL
NOT DETERMINISTIC
RETURN FLOOR(value_minimum + RAND() * (value_maximum - value_minimum + 1));
The function to get the next id:
DROP FUNCTION IF EXISTS next_invoice_id_val;
DELIMITER //
CREATE FUNCTION next_invoice_id_val ()
RETURNS BIGINT(8)
LANGUAGE SQL
NOT DETERMINISTIC
BEGIN
DECLARE lastId BIGINT(8) DEFAULT 1;
DECLARE randId BIGINT(8) DEFAULT 1;
DECLARE newId BIGINT(8) DEFAULT 1;
DECLARE nextId BIGINT(8) DEFAULT 1;
SELECT (SELECT MAX(`id`) FROM `invoices`) INTO lastId;
SELECT (SELECT random_integer(1,10)) INTO randId;
SELECT ( lastId + randId ) INTO nextId;
IF lastId IS NULL
THEN
SET newId = randId;
ELSE
SET newId = nextId;
END IF;
RETURN newId;
END //
DELIMITER ;
SELECT next_invoice_id_val();
and the trigger:
DROP TRIGGER IF EXISTS next_invoice_id_val_trigger;
DELIMITER //
CREATE TRIGGER next_invoice_id_val_trigger
BEFORE INSERT
ON invoices FOR EACH ROW
BEGIN
SET NEW.id = next_invoice_id_val();
END//
DELIMITER ;
That work like a charm, now if we want to generalize the behaviour to all tables.
We need a procedure to execute the query on any specific tables:
DROP PROCEDURE IF EXISTS last_id;
DELIMITER //
CREATE PROCEDURE last_id (IN tableName VARCHAR(50), OUT lastId BIGINT(8))
COMMENT 'Gets the last id value'
LANGUAGE SQL
NOT DETERMINISTIC
READS SQL DATA
BEGIN
SET #s := CONCAT('SELECT MAX(`id`) FROM `',tableName,'`');
PREPARE QUERY FROM #s;
EXECUTE QUERY;
DEALLOCATE PREPARE QUERY;
END //
DELIMITER ;
CALL last_id('invoices', #nextInvoiceId);
SELECT #nextInvoiceId;
The procedure for the next id value:
DROP PROCEDURE IF EXISTS next_id_val;
DELIMITER //
CREATE PROCEDURE next_id_val (IN tableName VARCHAR(50), OUT nextId BIGINT(8))
COMMENT 'Give the Next Id value + a random value'
LANGUAGE SQL
NOT DETERMINISTIC
READS SQL DATA
BEGIN
DECLARE randId BIGINT(8) DEFAULT 1;
SELECT (SELECT random_integer(1,10)) INTO randId;
CALL last_id(tableName, #currentId);
IF #currentId IS NULL
THEN
SET nextId = randId;
ELSE
SELECT ( #currentId + randId ) INTO nextId;
END IF;
END //
DELIMITER ;
CALL next_id_val('invoices', #nextInvoiceId);
SELECT #nextInvoiceId;
and the trigger:
# Call the procedure from a trigger
DROP TRIGGER IF EXISTS next_invoice_id_val_trigger;
DELIMITER //
CREATE TRIGGER next_invoice_id_val_trigger
BEFORE INSERT
ON invoices FOR EACH ROW
BEGIN
CALL next_id_val('invoices', #nextInvoiceId);
SET NEW.id = #nextInvoiceId;
END//
DELIMITER ;
and we get => Dynamic SQL is not allowed in stored function or trigger
I've read that storing in a temporary table might be a workaround, but as all posts have between 5 to 10 years old, I think we might have a better solution for such a straightforward case.
What is the workaround for using dynamic SQL in a stored Procedure
#1336 - Dynamic SQL is not allowed in stored function or trigger
Calling stored procedure that contains dynamic SQL from Trigger
Alternatives to dynamic sql in stored function
I'm trying use mysql to iterate through my database and convert strings to have only numbers and . in order to convert that column into a float from a varchar.
However, when I call the stored proc, it doesn't seem to actually change the datatable. I was hoping somebody could help me figure out what's wrong?
use mydb;
SET GLOBAL log_bin_trust_function_creators = 1;
CREATE TABLE IF NOT EXISTS `docs` (
`id` int(6) unsigned NOT NULL,
`rev` int(3) unsigned NOT NULL,
`content` varchar(200) NOT NULL,
PRIMARY KEY (`id`,`rev`)
) DEFAULT CHARSET=utf8;
-- INSERT INTO `-- docs` (`id`, `rev`, `content`) VALUES
-- ('1', '1', '0.0 '),
-- ('2', '1', '2,765'),
-- ('3', '1', '*'),
-- ('4', '1', '0.7665');
DROP FUNCTION IF EXISTS floatify;
DELIMITER //
CREATE FUNCTION floatify(str VARCHAR(200)) RETURNS VARCHAR(16)
BEGIN
DECLARE i, len SMALLINT DEFAULT 1;
DECLARE ret VARCHAR(16) DEFAULT '';
DECLARE c CHAR(1);
SET len = CHAR_LENGTH( str );
REPEAT
BEGIN
SET c = MID( str, i, 1 );
IF c REGEXP '[0-9|.]' THEN
SET ret=CONCAT(ret,c);
END IF;
SET i = i + 1;
END;
UNTIL i > len END REPEAT;
RETURN ret;
END//
DELIMITER ;
DROP PROCEDURE IF EXISTS tofloat;
DELIMITER //
CREATE PROCEDURE tofloat()
BEGIN
DECLARE currentid INT DEFAULT 1;
DECLARE RowCnt BIGINT DEFAULT 0;
SELECT RowCnt = COUNT(*) FROM docs;
WHILE currentid <= RowCnt DO
UPDATE docs
SET content = floatify(content)
WHERE id = currentid;
SET currentid = currentid + 1 ;
END WHILE;
-- ALTER TABLE docs
-- MODIFY content FLOAT NOT NULL DEFAULT 0 ;
END//
DELIMITER ;
-- select * from docs;
CALL tofloat();
select * from docs;
SET RowCnt = (SELECT COUNT(*) FROM docs); fixed it
You can set a variable to be the result of a subquery within a proc.
Get SQL to do the work:
ALTER TABLE t ADD COLUMN cfloat FLOAT;
UPDATE t SET cfloat = 0 + content;
ALTER TABLE t
CHANGE COLUMN content content_str VARCHAR(200) NOT NULL,
CHANGE COLUMN cfloat content FLOAT NOT NULL;
...check the results
ALTER TABLE t
DROP COLUMN content;
In Postgresql, trigger can be created by using trigger procedure. This is handy way of creating trigger. Using the same trigger procedure, it is possible to create several triggers and apply it even for several different tables. I am wondering if there is any MySQL equivalent for it. I am inspired by this blog post which creates a generic trigger for database auditing. My plan is to implement the similar approach by using MySQL. But, is it really possible create that kind of generic trigger by MySQL?
After doing some research, I have understood that there is no direct way to create generic trigger in MySQL. Even dynamic SQL like prepare statement, execute statement are not allowed inside trigger in MySQL.
I have found a workaround to generate trigger dynamically. Suppose we have a customer table:
CREATE TABLE customer (
id bigint(20) NOT NULL AUTO_INCREMENT,
created_on datetime DEFAULT NULL,
first_name varchar(100) NOT NULL,
last_name varchar(100) NOT NULL,
PRIMARY KEY (id)
)
A revision info table:
CREATE TABLE REVINFO (
REV int(11) NOT NULL AUTO_INCREMENT,
REVTSTMP bigint(20) DEFAULT NULL,
PRIMARY KEY (REV)
)
An audit table:
CREATE TABLE customer_AUD (
id bigint(20) NOT NULL,
REV int(11) NOT NULL,
REVTYPE tinyint(4) DEFAULT NULL,
created_on datetime DEFAULT NULL,
first_name varchar(100) DEFAULT NULL,
last_name varchar(100) DEFAULT NULL,
PRIMARY KEY (id, REV),
KEY FK_REV (REV)
)
Now we will crate a procedure that will take a table name and generate SQL for create audit related trigger for table.
DROP PROCEDURE IF EXISTS `proc_trigger_generator`;
DELIMITER $$
CREATE PROCEDURE `proc_trigger_generator` (IN tableName VARCHAR(255))
BEGIN
DECLARE triggerSQL TEXT DEFAULT "";
DECLARE cols TEXT DEFAULT "";
DECLARE col_values TEXT DEFAULT "";
DECLARE insert_query TEXT DEFAULT "";
DECLARE colName TEXT DEFAULT "";
DECLARE done INT DEFAULT FALSE;
DECLARE cursorDS CURSOR FOR SELECT column_name FROM information_schema.columns cols
WHERE cols.table_name = CONCAT(tableName, '_AUD')
and (column_name != 'REV' && column_name != 'REVTYPE');
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
SET triggerSQL = 'DELIMITER ;; \n\n';
SET triggerSQL = CONCAT(triggerSQL, 'drop trigger if exists tr_', tableName, '_update_audit;; \n\n');
SET triggerSQL = CONCAT(triggerSQL, 'create trigger tr_', tableName, '_update_audit \n');
SET triggerSQL = CONCAT(triggerSQL, 'after update \n');
SET triggerSQL = CONCAT(triggerSQL, '\t on ', tableName, '\n');
SET triggerSQL = CONCAT(triggerSQL, 'for each row \n');
SET triggerSQL = CONCAT(triggerSQL, 'begin \n');
SET triggerSQL = CONCAT(triggerSQL, '\t DECLARE tmpInt INT; \n');
SET triggerSQL = CONCAT(triggerSQL, '\t SELECT COALESCE(MAX(REV), 0) FROM REVINFO into tmpInt; \n\n');
SET triggerSQL = CONCAT(triggerSQL, '\t INSERT INTO REVINFO (REV, REVTSTMP) VALUES (tmpInt+1, CURRENT_TIMESTAMP()); \n\n');
SET insert_query = CONCAT(insert_query, 'INSERT INTO ', CONCAT(tableName, '_AUD'), ' (');
OPEN cursorDS;
ds_loop: LOOP
FETCH cursorDS INTO colName;
IF done THEN
LEAVE ds_loop;
END IF;
SET cols = CONCAT(cols, colName, ', ');
SET col_values = CONCAT(col_values, 'new.', colName, ', ');
END LOOP;
SET insert_query = CONCAT(insert_query, cols, 'REV, REVTYPE) VALUES \n');
SET insert_query = CONCAT(insert_query, '\t\t(', col_values, 'tmpInt+1, 1', ');');
CLOSE cursorDS;
SET triggerSQL = CONCAT(triggerSQL, '\t ',insert_query, ' \n\n');
SET triggerSQL = CONCAT(triggerSQL, 'end;; \n\n');
SET triggerSQL = CONCAT(triggerSQL, 'DELIMITER ; \n\n');
SELECT triggerSQL;
END $$
DELIMITER ;
call proc_trigger_generator('customer');
Calling the procedure by using customer table name generates SQL for the desired trigger:
DELIMITER ;;
drop trigger if exists tr_customer_update_audit;;
create trigger tr_customer_update_audit
after update
on customer
for each row
begin
DECLARE tmpInt INT;
SELECT COALESCE(MAX(REV), 0) FROM REVINFO into tmpInt;
INSERT INTO REVINFO (REV, REVTSTMP) VALUES (tmpInt+1, CURRENT_TIMESTAMP());
INSERT INTO customer_AUD (id, created_on, first_name, last_name, REV, REVTYPE) VALUES
(new.id, new.created_on, new.first_name, new.last_name, tmpInt+1, 1);
end;;
DELIMITER ;
The above trigger should do auditing tasks for customer table.
The trigger generator procedure can be applied to any other table now that we wish to apply auditing related tasks.
I created two columns in student table for my database. I now need to create a cursor for the student table. I need to make use of the input parameters for start and end student Id’s to filter the results in the cursor query.
I also need to open the cursor created and check if the student has an email assigned or not. If the email is not assigned I need to update the email column to have an email assigned to the student.
Finally to why I want help:
I cannot figure out how I would write the case statements for this cursor. I have tried to think of a good way to do this and not succeeded. Please help!!
DELIMITER $
DROP PROCEDURE IF EXISTS CURSOR_DEMO$
CREATE PROCEDURE CURSOR_DEMO(start_student_id INT
,end_student_id INT
)
BEGIN
DECLARE l_table_name VARCHAR(50);
DECLARE iam_done INT DEFAULT 0;
DECLARE l_sql_stmt VARCHAR(5000);
SET #l_sql_stmt='ALTER TABLE STUDENT ADD EMAIL VARCHAR';
SELECT #l_sql_stmt;
prepare stmt from #l_sql_stmt;
execute stmt;
SET #l_sql_stmt='ALTER TABLE STUDENT ADD PHONE int(10)';
SELECT #l_sql_stmt;
prepare stmt from #l_sql_stmt;
execute stmt;
DECLARE TBL_CUR CURSOR FOR
SELECT EMAIL FROM STUDENT.TABLES WHERE TABLE_SCHEMA='MYSQLDB';
BEGIN
DECLARE CONTINUE HANDLER FOR NOT FOUND SET IAM_DONE=1;
OPEN TBL_CUR;
tbl_loop:LOOP
FETCH tbl_cur INTO l_table_name;
IF IAM_DONE = 1 THEN
LEAVE tbl_loop;
END IF;
CASE WHEN l_table_name = 'STUDENT' THEN
ELSE BEGIN END;
END CASE;
END LOOP tbl_loop;
CLOSE TBL_CUR;
END;
END$
DELIMITER ;
Is this the kind of thing you need?
/*
drop table student;
delimiter $$
CREATE TABLE `student` (
`id` int(11) NOT NULL ,
`name` char(1) NOT NULL,
`email` varchar(1),
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8$$
drop table email;
delimiter $$
CREATE TABLE `email` (
`id` int(11) NOT NULL ,
`type` varchar(8) NOT NULL,
`person_id` int,
`email` varchar(1),
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8$$
;
*/
DELIMITER $
DROP PROCEDURE IF EXISTS CURSOR_DEMO$
CREATE PROCEDURE CURSOR_DEMO(start_student_id INT
,end_student_id INT)
BEGIN
declare email_person_id int;
declare email_address varchar(50);
DECLARE done INT DEFAULT 0;
DECLARE CUR CURSOR FOR
SELECT person_id,email FROM sandbox.email where type = 'student';
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;
OPEN CUR;
cur_loop:LOOP
IF done = 1 THEN
LEAVE cur_loop;
END IF;
FETCH CUR INTO email_person_id,email_address;
update student
set email = email_address
where id = email_person_id
and email is null
;
END LOOP cur_loop;
CLOSE CUR;
commit;
END$
DELIMITER ;
truncate table student;
insert into student
values
(1,'A','1'),
(2,'B','1'),
(3,'C',null),
(4,'D',null),
(5,'E',null),
(6,'G',null),
(7,'F',null)
;
truncate table email;
insert into email
values
(1,'student',1,'a'),
(2,'student',2,'b'),
(3,'faculty',7,'z'),
(4,'student',3,'c')
;
select * from student;
call cursor_demo(1,10);
select * from student;
I am trying to get this procedure to work and it is stumping me. I simply want this procedure to populate a temp table with the separated values from a table of CSV values.
DELIMITER $$
DROP PROCEDURE IF EXISTS String_Split $$
CREATE PROCEDURE String_Split
(
vString VARCHAR(255),
vSeparator VARCHAR(5)
)
BEGIN
DECLARE vDone tinyint(1) DEFAULT 1;
DECLARE vIndex INT DEFAULT 1;
DECLARE vSubString VARCHAR(15);
DROP TABLE IF EXISTS tmpValues;
CREATE TEMPORARY TABLE tmpValues (tmpVal VARCHAR(255));
WHILE vDone > 0 DO
SET vSubString = SUBSTRING(vString, vIndex,
IF(LOCATE(vSeparator, vString, vIndex) > 0,
LOCATE(vSeparator, vString, vIndex) - vIndex,
LENGTH(vString)
));
IF LENGTH(vSubString) > 0 THEN
SET vIndex = vIndex + LENGTH(vSubString) + 1;
INSERT INTO tmpValues VALUES (vSubString);
ELSE
SET vDone = 0;
END IF;
END WHILE;
END; $$
I call on it:
CALL String_Split(my_csv.keywords, ',');
And I get this:
Error Code: 1109. Unknown table 'my_csv' in field list
I'm not getting this because the table is there and the appropriate database is selected.
CREATE TABLE `my_csv` (
`id` int(10) NOT NULL AUTO_INCREMENT,
`keywords` text NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 $$
INSERT INTO `my_csv` () VALUES
(1, 'featured, 3/8, Diamond, Engagement Ring, 14K, White Gold, Gold'),
(2, '1/3, Diamond, Engagement Ring, 14K, White Gold, Gold'),
(3, 'featured') $$
Instead of calling the table name and field in the call function, you need to get the value first, then call the procedure. Here's a working example.
SELECT #keyword :=keywords from my_csv;
CALL String_Split(#keyword, ',');
Edit:
That only grabbed the last row. This one selects all of them. Also, doing this the vSeparator variable in the procedure was too small, so I bumped that up to 255.
SELECT #keyword :=group_concat(keywords) FROM my_csv;
CALL String_Split(#keyword, ',');
select * from tmpValues;