I have some of tables with identical field values which must not be repeated. I decided to make the generation of value when making INSERT. Trigger getting maximum value and add 1. But after SELECT MAX(account_number) AS last_account_number INTO last_account_number FROM companies; last_account_number always null, but the value is there and the request outside trigger itself runs smoothly.
CREATE TRIGGER generate_account_number_for_companies
before insert
ON companies FOR EACH ROW
BEGIN
DECLARE account_number INT;
DECLARE last_account_number INT;
SELECT MAX(account_number) AS last_account_number INTO last_account_number FROM companies;
IF last_account_number is null THEN
SET New.account_number = 10000000;
ELSE
SET New.account_number = last_account_number + 1;
END IF;
END
First, you do not need the AS last_account_number part in your SELECT ... INTO statement. Second, do you have data in your companies table currently, or is it empty? If it is not empty, try modifying the statement to exclude NULL values:
SELECT MAX(account_number) INTO last_account_number FROM companies WHERE account_number IS NOT NULL;
You could also add a coalesce in there to set it to 0 in the event of a NULL return.
SELECT COALESCE(MAX(account_number), 0) INTO last_account_number FROM companies WHERE account_number IS NOT NULL;
You also are declaring a variable with the same name as your column that you are trying to select, remove the line: DECLARE account_number INT; from your trigger.
Related
I am working on a procedure which sells my items. When I try to call it, it tells me that error message. I checked which part returns more rows, but I couldn't figure it out. Here is the code for that procedure:
DELIMITER //
CREATE PROCEDURE SellItem(pCharacterName varchar(50), pItemName varchar(50), howManyItems int(11))
BEGIN
DECLARE pchar int(11);
DECLARE pitem int(11);
DECLARE pitemCost int(11);
DECLARE pcharMoney int(11);
DECLARE newMoneyValue int(11);
DECLARE cnt int(11) DEFAULT 1;
DECLARE pcharitid int(11);
SET pchar=(SELECT `getChar`(`pCharacterName`));
SET pitem=(SELECT `getItem`(`pItemName`));
SET pitemCost=(SELECT `price` FROM `item` WHERE `item`.`item_id`=pitem);
SET pcharMoney=(SELECT `money` FROM `character` WHERE `character`.`character_id`=pchar);
SET newMoneyValue=pcharMoney;
WHILE cnt<=`howManyItems` DO
SET newMoneyValue=newMoneyValue+pitemCost;
SET cnt=cnt+1;
END WHILE;
SET cnt=1;
WHILE cnt<=`howManyItems` DO
SET pcharitid=(SELECT MAX(`character_item_id`) FROM `character_item` WHERE `character_item`.`character_id`=pchar AND `character_item`.`item_id`=pitem);
IF (SELECT `item_id` FROM `character_item` WHERE `character_item`.`item_id` IN(SELECT `item_id` FROM `item` WHERE `item`.`name`=`pItemName`)) THEN
DELETE FROM `character_item` WHERE `character_item`.`character_item_id`=pcharitid;
UPDATE `character` SET `money`=newMoneyValue WHERE `character`.`character_id`=pchar;
SET cnt=cnt+1;
END IF;
END WHILE;
END; //
DELIMITER ;
The functions I call are simple functions which return me the ID of the selected character/item.
When you call a SELECT in a context that requires only one value, but the SELECT isn't logically guaranteed to return only one value, then you get this error.
You have six SELECT operations:
SET pchar=(SELECT `getChar`(`pCharacterName`));
SET pitem=(SELECT `getItem`(`pItemName`));
These two are calling a stored function on a scalar parameter. They are okay because in both cases, it can only return one value.
SET pitemCost=(SELECT `price` FROM `item` WHERE `item`.`item_id`=pitem);
This SELECT is probably okay. I'm assuming item.item_id is the primary key of that table, so it can match only one row (or zero rows).
SET pcharMoney=(SELECT `money` FROM `character` WHERE `character`.`character_id`=pchar);
Likewise, this seems okay, assuming character.character_id is a primary key.
SET pcharitid=(SELECT MAX(`character_item_id`) FROM `character_item` WHERE `character_item`.`character_id`=pchar AND `character_item`.`item_id`=pitem);
This is sure to return only one value, because you're using MAX() and the query has no GROUP BY.
IF (SELECT `item_id` FROM `character_item` WHERE `character_item`.`item_id` IN
(SELECT `item_id` FROM `item` WHERE `item`.`name`=`pItemName`)) THEN
The inner subquery doesn't need to be a scalar, because it's part of an IN() predicate, which can compare against multiple values.
The outer query must be a scalar query, but it's not. It is possible to match multiple rows, depending on your data, so it cannot be logically used in an IF() condition.
You can fix it either my using SELECT MAX(item_id)... or by using ...LIMIT 1 at the end of the query.
You are going to have to run each function individually with the test data you are using to establish which one is returning more than one row.
E.g. first run this:
SELECT 'getChar' ('pCharacterName')
But obviously replacing pCharacterName with your test data.
i'm trying to update 2 column with trigger before insert, but i have unexpected result. i insert some data and the 2 last column will automatically inserted with values, here my first attempt
see? the last 2 column is null even i set some trigger and function to fill that columns automatically. Here my second attempt WITH EXACTLY SAME DATA
the last 2 column is filled with data, but i don't understand why the first attempt is fail?
here my trigger i use in the column total_harga
CREATE TRIGGER `set_total_harga` BEFORE INSERT ON `tbl_transaksi_detail`
FOR EACH ROW BEGIN
set NEW.total_harga = hitungTotalHargaPerItem(NEW.qty, NEW.harga_satuan);
END
trigger for column harga_satuan
CREATE TRIGGER `set_harga_satuan` BEFORE INSERT ON `tbl_transaksi_detail`
FOR EACH ROW BEGIN
set NEW.harga_satuan = set_Harga_Unit(NEW.unit, NEW.id_barang, NEW.no_transaksi);
END
function set_Harga_Unit
BEGIN
DECLARE
q,
id_toko INT;
SET
id_toko =(
SELECT DISTINCT
`tbl_transaksi`.`id_toko`
FROM
`tbl_transaksi`,
`tbl_transaksi_detail`
WHERE
`tbl_transaksi`.`no_transaksi` = no_trans
); IF unit = "PCS" THEN
SET
q =(
SELECT
`tbl_harga_jual`.`harga_pcs`
FROM
`tbl_harga_jual`
WHERE
`tbl_harga_jual`.`id_barang` = id_brg AND `tbl_harga_jual`.`id_toko` = id_toko
); RETURN q; ELSEIF unit = "PAK" THEN
SET
q =(
SELECT
`tbl_harga_jual`.`harga_pak`
FROM
`tbl_harga_jual`
WHERE
`tbl_harga_jual`.`id_barang` = id_brg AND `tbl_harga_jual`.`id_toko` = id_toko
); RETURN q; ELSEIF unit = "KARTON" THEN
SET
q =(
SELECT
`tbl_harga_jual`.`harga_karton`
FROM
`tbl_harga_jual`
WHERE
`tbl_harga_jual`.`id_barang` = id_brg AND `tbl_harga_jual`.`id_toko` = id_toko
); RETURN q;
END IF; RETURN q;
END
function hitungTotalHargaPerItem
BEGIN
DECLARE hasil int;
set hasil = qty * harga_satuan;
RETURN hasil;
END
The root cause serms to be the select that sets id_toko variable's value:
SET
id_toko =(
SELECT DISTINCT
`tbl_transaksi`.`id_toko`
FROM
`tbl_transaksi`,
`tbl_transaksi_detail`
WHERE
`tbl_transaksi`.`no_transaksi` = no_trans
);
In the select you inner join tbl_transaksi_detail (the table with the trigger in question) on another table. However, in the 1st case tbl_transaksi_detail is still empty (the trigger is before insert), therefore id_toko variable is set to null.
This will result q being null, which in turn results in the entire calculation set to null.
In the 2nd case there is already a record inserted into tbl_transaksi_detail table, therefore the calculation returns a non null value. But it returns the correct values only because the 1st and 2nd records' details are exactly the same.
I do not really understand that select that calculates id_toko anyway. If that is a transaction id, then you may use last_insert_id() if it is auto increment and the transaction record has just been created or max(id_toko) to get the highest value of id_toko (this is not multi user safe).
it seem i have mistaken select query in function set_Harga_Unit, based on clues from #Shadow
SET
id_toko =(
SELECT DISTINCT
`tbl_transaksi`.`id_toko`
FROM
`tbl_transaksi`,
`tbl_transaksi_detail`<<== I DON'T NEED THIS
WHERE
`tbl_transaksi`.`no_transaksi` = no_trans
); IF unit = "PCS" THEN
when first insert in tbl_transaksi_detail, the value no_transaksi is null because i use trigger before insert in empty table (tbl_transaksi_detail), so i remove tbl_transaksi_detail from query
SET
id_toko =(
SELECT DISTINCT
`tbl_transaksi`.`id_toko`
FROM
`tbl_transaksi`
WHERE
`tbl_transaksi`.`no_transaksi` = no_trans
); IF unit = "PCS" THEN
now it working, thanks everybody!
i have a trigger like below, the logic is to change FID status after fidRule status changed.
in my app, i update 1 row in each statement,
but i found sometimes(very rare) the trigger not firing.
ALTER TRIGGER [dbo].[triggerSetFIDStatus]
ON [dbo].[FIDRules]
AFTER UPDATE
AS
BEGIN
set nocount on
DECLARE #ruleStatus INT
DECLARE #newRuleStatus INT
DECLARE #FIDAlertStatus INT
DECLARE #FIDId INT
DECLARE #isFIDEnabled int
DECLARE #ruleId INT
SELECT #ruleStatus = deleted.alertStatus,
#FIDId = deleted.FIDID,
#ruleId = deleted.id
from
deleted
SELECT #newRuleStatus = inserted.alertStatus
from
inserted
SELECT #FIDAlertStatus = alertStatus,
#isFIDEnabled= isEnabled
FROM FID
WHERE id = #FIDId
IF #FIDAlertStatus <> #newRuleStatus
BEGIN
-- change FID-status by FIDRule-status
UPDATE [dbo].[FID] SET alertStatus=#newRuleStatus WHERE id=#FIDId
END
IF #newRuleStatus >= 0 AND #newRuleStatus <> #ruleStatus
UPDATE [dbo].[FIDRules] SET isAlertStatChanged=1, AlertStatChangeTime = SYSUTCDATETIME() WHERE id=#ruleId
END
The trigger will not be fired if the UPDATE statement fails or another triggers fails to execute before this trigger is fired.
One comment about your trigger itself:
You are expecting one records from DELETED which is not always correct.
Please make your trigger robust enough in case DELETED contains multiple records
-- What if deleted contains multiple records?
SELECT #ruleStatus = deleted.alertStatus,
#FIDId = deleted.FIDID,
#ruleId = deleted.id
FROM
deleted
You can either use SELECT TOP(1) or make sure your trigger is able to handle multiple records from the DELETED list.
I've been Googleing around for a while and I am sure that the problem is that I don't understand clearly how CURSORs in MySQL work.
A short explanation of the problem: I'm writing such function (simplified):
CREATE DEFINER=`me`#`localhost` FUNCTION `product_move`(prID INT, tr_type VARCHAR(2), clID INT, am INT, dnID INT, usrID INT, price FLOAT(10,2), ti DATETIME, barc TINYTEXT, cmt TINYTEXT, lnID INT)
BEGIN
DECLARE done INT DEFAULT FALSE;
DECLARE cur_id INT;
DECLARE net_pr FLOAT(10,2);
DECLARE cur_r INT;
DECLARE remaind INT DEFAULT 0;
DECLARE avg_price FLOAT(10,2) DEFAULT 0;
DECLARE curs CURSOR FOR SELECT `products_transactionsID`,
`price`,
`remains`
FROM `products_transactions`
WHERE `productID`=prID AND `remains`>0 AND `type`='V'
ORDER BY `products_transactionsID` ASC;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
OPEN curs;
SET remaind=am;
read_loop:LOOP
FETCH curs INTO cur_id,net_pr,cur_r;
IF done THEN
LEAVE read_loop;
END IF;
IF (cur_r>=remaind) THEN
SET avg_price = avg_price + (net_pr * remaind);
UPDATE `products_transactions` SET `remains`=`remains`-remaind WHERE products_transactionsID=cur_id;
LEAVE read_loop;
ELSE
SET avg_price = avg_price + (net_pr * cur_r);
SET remaind=remaind-cur_r;
UPDATE `products_transactions` SET `remains`=0 WHERE products_transactionsID=cur_id;
END IF;
END LOOP;
CLOSE curs;
SET avg_price=avg_price/am;
INSERT INTO products_transactions
(`products_transactionsID`,`clientID`,`date_created`,`delivery_notesID`,`type`,`productID`,`amountIN`,`amountOUT`,`barcodes`,`in_stock`,`out_stock`,`out_repair`,`out_loss`,`booked`,`ordered`,`userID`,`price`,`comments`,`fifo_buy_price`)
SELECT NULL, clID, ti, dnID , tr_type, prID, 0, am, barc, products_transactions.in_stock-am, products_transactions.out_stock,
products_transactions.out_repair, products_transactions.out_loss, products_transactions.booked, products_transactions.ordered,usrID,price,cmt,avg_price
FROM
products_transactions WHERE productID=prID ORDER BY products_transactionsID DESC LIMIT 1;
So, we insert a new row in this table, based upon some calculations from the previously selected rows and updating these rows meanwhile.
The problem is with the avg_price variable, which should be calculated based on the net_pr variable which is FETCH'ed from the cursor. But somehow, instead of being FETCH'ed from the SELECT, the net_pr variable takes the value of the price input parameter of my function! How is that possible?
My guesses have been so far:
a variable name conflict? Searched through the code but I can't find any.
updating the table within the LOOP could make the CURSOR loose its position? It would make sense, but that wouldn't result in this, either...
I'd apreciate any ideas.
Two things that I can see:
1) Don't update the table that you're using in the cursor. MySQL says the cursor is read only but I wouldn't trust this. Set your value, exit the cursor, and then update the table.
2) Using the same name for a variable in the proc definition and a column in a select gives a conflict: http://dev.mysql.com/doc/refman/5.0/en/local-variable-scope.html
"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 want to generate PK through trigger as it is custom PK.
It is like depending on the member type field, I want to generate member id which is PK.
e.g. if new record's member type is DGIA, then member id will be DGIA1, DGIA2, DGIA3 ...and so on... if member type is DGIL, then member id will be DGIL1, DGIL2, DGIL3 ...and so on...
So, how to write trigger for the same... I have tried as following but it is working for 1st record only.
ALTER TRIGGER [dbo].[next_member_id] ON [dbo].[DAD_MEMBERSHIP] AFTER INSERT
AS
BEGIN
DECLARE #COUNT INT
SET #COUNT=0;
SELECT #COUNT=ISNULL(MAX(CAST(SUBSTRING(DAD_MEMBERSHIP.MEMBER_ID,5,15) AS INT)),0)+1 FROM DAD_MEMBERSHIP where DAD_MEMBERSHIP.MEMBER_TYPE = DAD_MEMBERSHIP.MEMBER_TYPE
update DAD_MEMBERSHIP set DAD_MEMBERSHIP.MEMBER_ID = DAD_MEMBERSHIP.MEMBER_TYPE + CONVERT(varchar,#COUNT)
from DAD_MEMBERSHIP inner join inserted on DAD_MEMBERSHIP.MEMBER_TYPE = inserted.MEMBER_TYPE
END
Triggers operate by batch of records, you cannot assign to a scalar variable and expect it to work for more than one record. You need to rethink your whole process into a set-based process.
I solved the problem using following trigger
ALTER TRIGGER [dbo].[next_member_id]
ON [dbo].[DAD_MEMBERSHIP]
AFTER INSERT
AS
BEGIN
DECLARE #COUNT INT
SET #COUNT=0;
DECLARE #STR VARCHAR(5)
SET #STR=''
select #STR=i.MEMBER_TYPE from inserted i;
SELECT #COUNT=ISNULL(MAX(CAST(SUBSTRING(DAD_MEMBERSHIP.MEMBER_ID,5,15) AS INT)),0)+1
from DAD_MEMBERSHIP where MEMBER_TYPE=#STR
update DAD_MEMBERSHIP set DAD_MEMBERSHIP.MEMBER_ID = #STR + CONVERT(varchar,#COUNT)
from DAD_MEMBERSHIP inner join inserted i on i.MEMBER_TYPE=DAD_MEMBERSHIP.MEMBER_TYPE where DAD_MEMBERSHIP.MEMBER_ID is null
END