I have a table called scheduler_sched which has several columns, including a column called schedule_id.
I need a function where I can pass 2 ids (copy_from_id, copy_to_id) as parameters. And what I need to do is take every row where schedule_id = copy_from_id AND duplicate it but change the copy_from_id to the copy_to_id
So basically I want to to the equivalient of this:
UPDATE scheduler_sched SET schedule_id = 32 WHERE schedule_id = 28
Only I do not want to UPDATE any rows, I want to create duplicates with the new ID's
Does this make sense?
How can I do this?
THANKS!
(By the way schedule_id is not a unique/index field on this table)
Insert into scheduler_sched (column1, column2, column3,schedule_id )
Select column1, column2, column3, 32 from scheduler_sched WHERE schedule_id = 28
I think that ON DUPLICATE KEY UPDATE syntax may help you:
http://dev.mysql.com/doc/refman/5.1/en/insert-on-duplicate.html
e.g.:
INSERT INTO table (a,b,c) VALUES (1,2,3)
ON DUPLICATE KEY UPDATE c=c+1;
Just INSERT a new row instead of updating. SELECT first if that schedule_id 28 exists, and if it does, insert a new one with that being the ID.
Since you haven't specified a version of MySQL, I'm going to assume that it is the lastest (5.4).
Assuming I am understanding you correctly, you should be able to implement this using triggers: http://dev.mysql.com/doc/refman/5.4/en/create-trigger.html
One of the benefits of using triggers, is it is all handled by the database itself.
Related
i don't know mysql very much. And i've problem about that. I've a database and it's 20 GB. I want to combine 4 columns and then move the combined column to the new one. But the problem is duplicated data in the table.
For example i wanna combine;
Column1(Not Null),
Column2(Some of them null, some of them not null),
Column3(Not Null),
Column4(Some of them null, some of them not null).
And my new column, which i want to move my combined columns, is fully empty. After my longly research, at last i find this code on dev.mysql.com
INSERT INTO my_table (new_content)
SELECT Column1
FROM my_table WHERE my_table > 0;
As a result, it moved Column1 to the new_content. But my the other 20 columns were duplicated too, as empty fields. How can i make it in an easy way?
Sorry for my bad English. Thanks in advance.
If you want a resulting column based on the string concatenation fo the column you can use concat
INSERT INTO my_table (new_content)
SELECT concat(Column1 , Column2, Column3, Column4)
FROM my_table ;
Create the column in already existing table:
ALTER TABLE my_table ADD COLUMN new_content VARCHAR(55);
Update table and concate all the columns to the newly created column:
UPDATE my_table SET new_content = CONCAT(Column1, Column2);
Create a trigger for all inserting values in future as well:
CREATE TRIGGER insert_trigger
BEFORE INSERT ON my_table
FOR EACH ROW
SET new.new_content = CONCAT(Column1, Column2);
You can also create a trigger for UPDATE:
CREATE TRIGGER
BEFORE UPDATE ON my_table
FOR EACH ROW
SET new.new_content = CONCAT(Column1, Column2);
I am running a insert statement to insert data, but I want to check for any duplicate entries based on date and then do an entry.
All I want is if today a user enters product_name='x', 'x' is unique so that no one can enter product name x again today. But of course the next day they can.
I do not want to run a select before the insert to do the checking. Is there an alternative?
You can either use
1. Insert into... on duplicate update
2. insert.. ignore
This post will answer your question
"INSERT IGNORE" vs "INSERT ... ON DUPLICATE KEY UPDATE"
You can use the mysql insert into... on duplicate update syntax which will basically enter in a new row if one isn't there, or if the new row would have caused a key constraint to kick in, then it can be used to update instead.
Lets say you have the following table:
MyTable
ID | Name
1 | Fluffeh
2 | Bobby
3 | Tables
And ID is set as the primary key in the database (meaning it CANNOT have two rows with the same value in it) you would normally try to insert like this:
insert into myTable
values (1, 'Fluffster');
But this would generate an error as there is already a row with ID of 1 in it.
By using the insert on duplicate update the query now looks like this:
insert into myTable
values (1, 'Fluffster')
on duplicate key update Name='Fluffster';
Now, rather than returning an error, it updates the row with the new name instead.
Edit: You can add a unique index across two columns with the following syntax:
ALTER TABLE myTable
ADD UNIQUE INDEX (ID, `name`);
This will now let you use the syntax above to insert rows while having the same ID as other rows, but only if the name is different - or in your case, add the constraint on the varchar and date fields.
Lastly, please do add this sort of information into your question to start with, would have saved everyone a bit of time :)
I have a small PHP Mysql function which generates all the columns within a mysql table, but I would like the function not to display the primary keys for each table just the other columns.
How can this be done, I havent been able to find the code for it.
Thanks
It seems I didnt explain the question well.
The mysql table from which the columns are generated is sent on demand from a list of ALL THE TABLE IN THE DB (over 150) and I cant specify the exact columns for each of the table.
It would just be more efficient if I found a way of omitting the primary key from the result.
Since it isnt required for the subsequent processing and quite confusing to the enduser as to its use.
Thanks
Use:
SELECT column1, column2, column3 FROM table
For what it's worth, returning the PK or not isn't going to break the bank.
In general, doing SELECT * FROM is bad, but if you're just going to do SELECT every, column, but, the, pk FROM then you may as well just select everything.
The best answer is just to SELECT the columns you need. If you need 3 columns, query for 3 columns and name them explicitly: SELECT column1, column2, column3 FROM table_name
I need to create a insert and update statement, when today date is not in the database it will insert else it will update the QTY (from excel [this part I have done]) get from today.
But, there have a lots of row need to be insert and update.
1) it will check for the last 4 days in database, if there doesn't include today, it will just insert the data for today and update the last 3 days data. in the other hand, if there contain today it will just update.
P.S: I had try to use INSERT... ON DUPLICATE KEY UPDATE but it only 1 row affected.
If else statement , when i used this it only insert one row of data then the rest it just doing update.
Can give me some advise or example.
suppose you bulk copy your data from excel to a temporary table tbl and your actual table is tbl1 then do something like this
begin transaction;
if not exists(select * from tbl(updlock holdlock) where...)
begin
insert into tbl1...
else
begin
update tbl1...
end
commit;
What language are you using to do this? I have done something similar in Ruby before. I would make the column (Date in your case) unique at the database level then simply try inserting each record. When I get an exception thrown because the Date is not unique I would then proceed to update the QTY.
I found this article on mysql which says it supports multiple insert.
http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html
INSERT INTO table (a,b,c) VALUES (1,2,3),(4,5,6)
ON DUPLICATE KEY UPDATE c=VALUES(a)+VALUES(b);
That statement is identical to the following two statements:
INSERT INTO table (a,b,c) VALUES (1,2,3)
ON DUPLICATE KEY UPDATE c=3;
INSERT INTO table (a,b,c) VALUES (4,5,6)
ON DUPLICATE KEY UPDATE c=9;
So if we want to edit straight, we could do something like this.
INSERT INTO table (uniquekey,data) VALUES (1,2),(4,5)
ON DUPLICATE KEY UPDATE data=VALUES(data);
I have a simple table made up of two columns: col_A and col_B.
The primary key is defined over both.
I need to update some rows and assign to col_A values that may generate duplicates, for example:
UPDATE `table` SET `col_A` = 66 WHERE `col_A` = 70
This statement sometimes yields a duplicate key error.
I don't want to simply ignore the error with UPDATE IGNORE, because then the rows that generate the error would remain unchanged. Instead, I want them to be deleted when they would conflict with another row after they have been updated
I'd like to write something like:
UPDATE `table` SET `col_A` = 66 WHERE `col_A` = 70 ON DUPLICATE KEY REPLACE
which unfortunately isn't legal in SQL, so I need help finding another way around.
Also, I'm using PHP and could consider a hybrid solution (i.e. part query part php code), but keep in mind that I have to perform this updating operation many millions of times.
thanks for your attention,
Silvio
Reminder: UPDATE's syntax has problems with joins with the same table that is being updated
EDIT: sorry, the column name in the WHERE clause was wrong, now I fixed it
Answer to revised question:
DELETE FROM
table_A
USING
table AS table_A
JOIN table AS table_B ON
table_A.col_B = table_B.col_B AND
table_B.col_A = 70
WHERE
table_A.col_A = 66
This gets rid of the rows that would cause problems. Then you issue your UPDATE query. Ideally you will do it all inside a transaction to avoid a situation where troublesome rows are re-inserted in between the two queries.
Are there any foreign keys referencing this table? If not then the following should do:
CREATE PROCEDURE `MyProcedure` (IN invarA INT, IN invarB INT)
LANGUAGE SQL
NOT DETERMINISTIC
MODIFIES SQL DATA
SQL SECURITY DEFINER
BEGIN
DELETE FROM table WHERE col_B = invarB;
IF ROW_COUNT() > 0 THEN
INSERT INTO table (`col_A`, `col_B`) VALUES (invarA, invarB);
END IF;
END
Example call:
CALL `MyProcedure`(66, 70)