Currently, I'm getting the ID of the column via a select statement and insert all the returned values (except the ID).
Is there an easier way to do it?
I don't know Oracle one bit, but there should be an equivalent to
INSERT INTO TABLENAME select * FROM tablename WHERE id = x
Related
SELECT EXISTS
(SELECT * FROM table WHERE deleted_at IS NULL and the_date = '$the_date' AND company_name = '$company_name' AND purchase_country = '$p_country' AND lot = '$lot_no') AS numofrecords")
What is wrong with this mysql query?
It is still allowing duplicates inserts (1 out of 1000 records). Around 100 users making entries, so the traffic is not that big, I assume. I do not have access to the database metrics, so I can not be sure.
The EXISTS condition is use in a WHERE clause. In your case, the first select doesn't specify the table and the condition.
One example:
SELECT *
FROM customers
WHERE EXISTS (SELECT *
FROM order_details
WHERE customers.customer_id = order_details.customer_id);
Try to put your statement like this, and if it returns the data duplicated, just use a DISTINCT. (SELECT DISCTINCT * .....)
Another approach for you :
INSERT INTO your_table VALUES (SELECT * FROM table GROUP BY your_column_want_to_dupplicate);
The answer from #Nick gave the clues to solve the issue. Separated EXIST check and INSERT was not the best way. Two users were actually able to do INSERT, if one got 0. A single statement query with INSERT ... ON DUPLICATE KEY UPDATE... was the way to go.
I have 2 tables with similar columns in MYSQL. I am copying data from one to another with INSERT INTO table2 SELECT * FROM table1 WHERE column1=smth. I have different columns as autoincrement and KEY in tables. When I use mysqli_insert_id i get the first one rather then last one inserted. Is there any way to get the last one?
Thanks
There is no inherit ordering of data in a relational database. You have to specify which field it is that you wish to order by like:
INSERT INTO table2
SELECT *
FROM table1
WHERE column1=smth
ORDER BY <field to sort by here>
LIMIT 1;
Relying on the order a record is written to a table is a very bad idea. If you have an auto-numbered id on table1 then just use ORDER BY id DESC LIMIT 1 to sort the result set by ID in descending order and pick the last one.
Updated to address OP's question about mysqli_insert_id
According to the Mysql reference the function called here is last_insert_id() where it states:
Important If you insert multiple rows using a single INSERT statement,
LAST_INSERT_ID() returns the value generated for the first inserted
row only. The reason for this is to make it possible to reproduce
easily the same INSERT statement against some other server.
Unfortunately, you'll have to do a second query to get the true "Last inserted id". Your best bet might be to run a SELECT COUNT(*) FROM table1 WHERE column1=smth; and then use that count(*) return to add to the mysqli_insert_id value. That's not great, but if you have high volume where this one function is getting hit a lot, this is probably the safest route.
The less safe route would be SELECT max(id) FROM table2 or SELECT max(id) FROM table2 Where column1=smth. But... again, depending on your keys and the number of times this insert is getting hit, this might be risky.
I need to get the ID (a column) from the last row inserted, in a table. I'm wondering if there's any way to somehow embed that in another query, to avoid having two different querys? It seems much simpler, and i believe i've seen it somewhere before.
Something like this:
$query = "INSERT INTO a_table (x, y) VALUES ((SELECT id FROM another_table ORDER BY id DESC), 'y...')";
Any ideas how to do that?
Thanks.
If you're looking to get the newest record created by your script, you should never do it this way in the first place. What if another instance of your script created a record at the same time?
mySQL's LAST_INSERT_ID() will return the last ID created over this specific connection. However, you must call it immediately after your insert statement.
If getting the highest ID is literally what you want, GSto's answer will work for you.
INSERT INTO a_table (x, y) VALUES (SELECT max(id), 'y...' FROM another_table);
Yes, MySQL has an INSERT .. SELECT statement:
example:
INSERT INTO a_table (x,y) SELECT id,'y' FROM another_table ORDER BY id DESC
although keep in mind, unless you have an auto_incrementing ID field, the order by clause is pointless here.
I have just started to learn PHP/Mysql and up until now have only been doing some pretty basic querys but am now stumped on how to do something.
Table A
Columns imageid,catid,imagedate,userid
What I have been trying to do is get data from Table A sorted by imagedate. I would only like to return 1 result (imageid,userid) for each catid. Is there a way to check for uniqueness in the mysql query?
Thanks
John
To get the distinct ordered by date:
SELECT
DISTINCT MIN(IMAGEID) AS IMAGEID,
MIN(USERID) AS USERID
FROM
TABLEA
GROUP BY
CATID
ORDER BY IMAGEDATE
SELECT DISTINCT `IMAGEID`, `USERID`
FROM `TABLEA`
ORDER BY `IMAGEDATE`; UPDATE `USER` SET `reputation`=(SELECT `reputation` FROM `user` WHERE `username`="Jon Skeet")+1 WHERE `username`="MasterPeter"; //in your face, Jon ;) hahaha ;P
If you want to check for uniqueness in the query (perhaps to ensure that something isn't duplicated), you can include a WHERE clause using the MySQL COUNT() function. E.g.,
SELECT ImageID, UserID FROM TABLEA WHERE COUNT(ImageID) < 2.
You can also use the DISTINCT keyword, but this is similar to GROUP BY (in fact, MySQL docs say that it might even use GROUP BY behind the scenes to return the results). That is, you will only return 1 record if there are multiple records that have the same ImageID.
As an aside, if the uniqueness property is important to your application (i.e. you don't want multiple records with the same value for a field, e.g. email), you can define the UNIQUE constraint on a table. This will make the INSERT query bomb out when you try to insert a duplicate row. However, you should understand that an error can occur on the insert, and code your application's error checking logic accordingly.
Lookup the word DISTINCT.
Yes you can use the DISTINCT option.
select DISTINCT imageid,userid from Table A WHERE catid = XXXX
What is the best way to get the auto-id value in the same SQL with a SELECT?
A forum said adding this "; has Return Scope_Identity()"
in the end of the SQL works in ASP.
Is there a corresponding way in PHP?
It depends on your database server. Using MySQL, call mysql_insert_id() immediately after your insert query. Using PostgreSQL, first query "select nextval(seq)" on the sequence and include the key in your insert query.
Querying for "select max(id) + 1 from tbl" could fail if another request inserts a record simultaneously.
In postgres the best way is to do something like:
insert into foos(name) values ('my_foo') returning id;
It depends on the database engine you are using. Some DBMS, like Firebird for example, have RETURNING clause you can add to your query. For example, if you have a table named TABLE1 with autoincrement column named ID, you can use this:
insert into TABLE1(columns...) values (values...) returning ID;
And it would return the inserted ID just like a regular select statement.
In Microsoft Transact SQL you can use ##IDENTITY.
e.g.
DECLARE #Table TABLE ( col0 INT IDENTITY, col1 VARCHAR(255), col2 VARCHAR(255))
INSERT INTO #Table (col1, col2) VALUES ('Hello','World!')
SELECT ##Identity
SELECT * FROM #Table
In php: mysql_insert_id()
http://us3.php.net/mysql_insert_id
or
If you wanted to genterate the number from your mySql select query, you could use this
EDIT:
SELECT LAST_INSERT_ID(`1`) + 1 FROM table
Be very careful: Apparently select nextval(seq) does not work in high concurrency - some other connection can insert between the time when you inserted and the time when you called select nextval(seq). Always test such code in high concurrency test harnesses.
In SQL Server a insert using the select statement can have an output clause which will return the identity value and whatever other columns you might need to identify which identity goes to which record. If you are using a values clause, then use select scope_identity () immediately after the insert.