I am facing this situation. I want to insert into a database like this :
INSERT INTO
`mytable` (`id`, `post_id`, `user_id`, `dtime`)
VALUES ('','$pid','$uid',NOW())"
The ID column is primary and with auto-increment. And I need to check if the post_id is not getting inserted twice.
Any idea on how to do that, so that if the post_id exists, it does an update, without needing two queries ?
Use the ON DUPLICATE KEY UPDATE syntax.
If you specify ON DUPLICATE KEY UPDATE, and a row is inserted that would cause a duplicate value in a UNIQUE index or PRIMARY KEY, MySQL performs an UPDATE of the old row.
http://dev.mysql.com/doc/refman/5.7/en/insert-on-duplicate.html
This link was the second result when I searched for "mysql insert or update" on Google.
Use a REPLACE query. It does exactly what you need, and looks like an INSERT except it starts with "REPLACE INTO"
http://dev.mysql.com/doc/refman/5.0/en/replace.html
My table just has single column ID (passwords for admin Log-in)
Because this code runs every time that program starts, I can prevent errors occurs on creating database and creating tables by using IF NOT EXIXTS statement.
Since adminLogin table should be initial first time, When user re-run the program, the Duplicate entry for primary key error occurs.
I used IF NOT EXISTS for inserting into table, But there is some another error!
My table:
Error:
You are trying to insert same value.
PK should be unique.
SET ID as autoincrement.
CREATE TABLE `table_code` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`your_column` varchar(45) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=latin1;
Another possibility
INSERT INTO adminLogin(ID) VALUES(100) ON DUPLICATE KEY UPDATE ID=ID;
You can use INSERT IGNORE instead.
INSERT IGNORE INTO ADMINLOGIN VALUES(200);
INSERT IGNORE
INSERT ... ON DUPLICATE KEY UPDATE ...
REPLACE INTO can all work without erroring. Depending on your needs, some may be a better use than others.
Here's a brief pros and cons of each:
INSERT IGNORE:
Pros: Easy to write
Cons: if data that is being inserted is newer the older data will be preserved
INSERT ... ON DUPLICATE KEY UPDATE ...
Pros: Can Insert or update specific columns that could have more recent data
Cons: A little harder to write the query for
REPLACE INTO
Pros: Can insert and update columns that could have more recent data. Faster than Insert, on duplicate key update.
Cons: Overwrites every column even though only some columns may have newer data. IF you are inserting multiple rows replace into could potentially overwrite data for existing rows that you don't really want to overwrite.
I am using MySQL 5.1.56, MyISAM. My table looks like this:
CREATE TABLE IF NOT EXISTS `my_table` (
`number` int(11) NOT NULL,
`name` varchar(50) NOT NULL,
`money` int(11) NOT NULL,
PRIMARY KEY (`number`,`name`)
) ENGINE=MyISAM;
It contains these two rows:
INSERT INTO `my_table` (`number`, `name`, `money`) VALUES
(1, 'S. Name', 150), (2, 'Another Name', 284);
Now I am trying to insert another row:
INSERT INTO `my_table` (`number`, `name`, `money`) VALUES
(2, 'S. Name', 240);
And MySQL just won't insert it while telling me this:
#1062 - Duplicate entry '2-S. Name' for key 'PRIMARY'
I really don't understand it. The primary key is on the first two columns (both of them), so the row I am trying to insert HAS a unique primary key, doesn't it?
I tried to repair the table, I tried to optimize the table, all to no avail. Also please note that I cannot change from MyISAM to InnoDB.
Am I missing something or is this a bug of MySQL or MyISAM? Thanks.
To summarize and point out where I think is the problem (even though there shouldn't be):
Table has primary key on two columns. I am trying to insert a row with a new combination of values in these two columns, but value in column one is already in some row and value in column two is already in another row. But they are not anywhere combined, so I believe this is supposed to work and I am very confused to see that it doesn't.
Your code and schema are OK. You probably trying on previous version of table.
http://sqlfiddle.com/#!2/9dc64/1/0
Your table even has no UNIQUE, so that error is impossible on that table.
Backup data from that table, drop it and re-create.
Maybe you tried to run that CREATE TABLE IF NOT EXIST. It was not created, you have old version, but there was no error because of IF NOT EXIST.
You may run SQL like this to see current table structure:
DESCRIBE my_table;
Edit - added later:
Try to run this:
DROP TABLE `my_table`; --make backup - it deletes table
CREATE TABLE `my_table` (
`number` int(11) NOT NULL,
`name` varchar(50) NOT NULL,
`money` int(11) NOT NULL,
PRIMARY KEY (`number`,`name`),
UNIQUE (`number`, `name`) --added unique on 2 rows
) ENGINE=MyISAM;
I know this wasn't the problem in this case, but I had a similar issue of "Duplicate Entry" when creating a composite primary key:
ALTER TABLE table ADD PRIMARY KEY(fieldA,fieldB);
The error was something like:
#1062 Duplicate entry 'valueA-valueB' for key 'PRIMARY'
So I searched:
select * from table where fieldA='valueA' and fieldB='valueB'
And the output showed just 1 row, no duplicate!
After some time I found out that if you have NULL values in these field you receive these errors. In the end the error message was kind of misleading me.
I had a similar issue, but in my case it turned out that I used case insensitive collation - utf8_general_ci.
Thus, when I tried to insert two strings which were different in a case-sensitive comparison, but the same in the case-insensitive one, MySQL fired the error and I couldn't understand what a problem, because I used a case-sensitive search.
The solution is to change the collation of a table, e.g. I used utf8_bin which is case-sensitive (or utf8_general_cs should be appropriate one too).
In case this helps anyone besides the OP, I had a similar problem using InnoDB.
For me, what was really going on was a foreign key constraint failure. I was referencing a foreign key that did not exist.
In other words, the error was completely off. The primary key was fine, and inserting the foreign key first fixed the problem. No idea why MySQL got this wrong suddenly.
Less common cases, but keep in mind that according to DOC https://dev.mysql.com/doc/refman/5.6/en/innodb-online-ddl-limitations.html
When running an online ALTER TABLE operation, the thread that runs the ALTER TABLE operation will apply an “online log” of DML operations that were run concurrently on the same table from other connection threads. When the DML operations are applied, it is possible to encounter a duplicate key entry error (ERROR 1062 (23000): Duplicate entry), even if the duplicate entry is only temporary and would be reverted by a later entry in the “online log”. This is similar to the idea of a foreign key constraint check in InnoDB in which constraints must hold during a transaction.
In my case the error was caused by the outdated schema, one column was originally varchar(50) but the dump I was trying to import was created from a modified version of the schema that has varchar(70) for that column (and some of the entries of that field where using more than 50 chars).
During the import some keys were truncated and the truncated version was not unique anymore. Took a while to figure that out, I was like "but this supposedly duplicated key doesn't even exist!".
Try with auto increment:
CREATE TABLE IF NOT EXISTS `my_table` (
`number` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(50) NOT NULL,
`money` int(11) NOT NULL,
PRIMARY KEY (`number`,`name`)
) ENGINE=MyISAM;
Your code is work well on this demo:
http://sqlfiddle.com/#!8/87e10/1/0
I think you are doing second query (insert...) twice. Try
select * from my_table
before insert new row and you will get that your data already exist or not.
i have just tried, and if you have data and table recreation wouldnt work, just alter table to InnoDB and try again, it would fix the problem
In case anyone else finds this thread with my problem -- I was using an "integer" column type in MySQL. The row I was attempting to insert had a primary key with a value larger than allowed by integer. Switching to "bigint" fixed the problem.
As per your code your "number" and "Name" are primarykey and you are inserting S.NAME in both row so it will make a conflict. we are using primarykey for accessing complete data. here you cant access the data using the primarykey 'name'.
im a beginner and i think it might be the error.
In my case the error was very misleading. The problem was that PHPMyAdmin uses "ALTER TABLE" when you click on the "make unique" button instead of "ALTER IGNORE TABLE", so I had to do it manually, like in:
ALTER TABLE mytbl ADD UNIQUE (columnName);
This problem is often created when adding a column or using an existing column as a primary key. It is not created due to a primary key existing that was never actually created or due to damage to the table.
What the error actually denotes is that a pending key value is blank.
The solution is to populate the column with unique values and then try to create the primary key again. There can be no blank, null or duplicate values, or this misleading error will appear.
For me a noop on table has been enough (was already InnoDB):
ALTER TABLE $tbl ENGINE=InnoDB;
tl;dr: my view showed my table was empty but the view excluded existing rows.
I had the same problem but mine was because I was inserting the same test rows I had used before. When I checked to see if my table was empty, I used a view that excluded different tenants so the search came back empty. When I checked the actual table, the previous records were still there.
Once I had deleted the existing records, the insert worked. Only half a day of frustration lost to this one...
Had this error, when adding a composite primary key that is ADD PRIMARY KEY (column1, column2, ...) The value of all the columns in that row must not be duplicated.
For Example:
You do ADD PRIMARY KEY (name, country, number)
name
country
number
collin
Uk
5
collin
Uk
5
This will throw an error #1062 - Duplicate entry 'collin-UK-5' for key 'PRIMARY' because the columns combined have duplicate
So if you see this format of error just check and ensure that the columns you want to add a composite primary key to combined don't have duplicates.
Another reason you may be getting this error is because the same restriction exists in another related table, and they Keyname on the related table has the exact same name. I've had this happen once and it was quite difficult to identify.
i.e. if you have a trigger that inserts data to a different table (the "related" table) with the same restriction and same Keyname, MySQL will not include the name of the table throwing the error, only the Keyname.
As looking on your error #1062 - Duplicate entry '2-S. Name' for key 'PRIMARY' it is saying that you use primary key in your number field that's why it is showing duplicate Error on Number Field.
So Remove this primary Key then it inset duplicate also.
Solution:
Place unique constraint on multiple columns
ALTER TABLE rating ADD UNIQUE KEY ( id , id );
I want to insert a score in my rating system. I want to be able to insert data if it doesn't exist. I also want the same query to return true/false if it does exist.
I looked into INSERT IGNORE but that silently fails so I don't know how to check against that.
I know I could attempt a SELECT ... WHERE id = 1 and THAN do the insert, but I want to move this down to a single insert, is this possible?
If you use a unique key constraint on the column or columns you want to check against, then a normal insert will succeed if there is no data already, or fail noisily due to unique key constraint if there is already something matching.
INSERT INTO `rating` (value1)
SELECT 'your rate for value1' FROM `rating`
WHERE NOT EXISTS (SELECT * FROM `rating`
WHERE value1='your rate for value1' ) LIMIT 1;
A standard problem in applications is to insert a record if one doesn't exist - or update if it does. In cases where the PRIMARY KEY is unknown this is usally solved by issuing a SELECT and then running either an INSERT or UPDATE if the record was found.
However, there seems to be at least three ways I know of that you can insert a record into a database even when a record already exists. Personally, I would rather drop the new insert request if one already exists, but then there might be cases where you would rather drop the record in the database and use the new one.
CREATE TABLE IF NOT EXISTS `table` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`foo` int(10) unsigned NOT NULL,
`bar` int(10) unsigned NOT NULL,
PRIMARY KEY (`id`),
KEY `row` (`foo`,`bar`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
Here are the three methods:
INSERT IGNORE INTO table (foo, bar) VALUES (2,3);
INSERT INTO table (foo, bar) VALUES (2,3) ON DUPLICATE KEY UPDATE;
REPLACE INTO table (foo, bar) VALUES (2,3);
At what times should each of these methods be used?
Can someone give some examples of correct usage scenarios?
INSERT should be used when you just want to insert a new row
Lets say you are storing log entries, you'll want to log every event, use INSERT.
INSERT IGNORE should be used when you just want there to be a specific key exists in the table, it doesn't matter if it's the current insert that creates it, or if it's already present.
Let's say you have a table of phone-numbers and the number of uses, you find a new phone number that you are not sure exists in the table, but you want it to be there.
You use INSERT IGNORE to make sure that it's there.
REPLACE INTO should be used when you want to make sure that a specific key exists in the table, if it exists you'd like the new values to be used, instead of that present.
You have another table with phone-numbers, this time you find a new number and a name to associate it with.
You use REPLACE INTO to find and update a complete record, or just insert the new information.
INSERT INTO ... ON DUPLICATE KEY UPDATE ...
Please not that this is not an alternative method of writing REPLACE INTO, the above should be used whenever you'd like to make sure that a specific key exists, but if it does update some of the columns, not all of them.
For example if you are storing the numbers of visits from a certain IP, and the first page the user ever visited.
INSERT INTO visitors (ip,visits,first_page) VALUES (<ip>,1,<current_page>) ON DUPLICATE KEY visits = visits +1;
In your question, you have
INSERT INTO `table` (foo, bar) VALUES (2,3) ON DUPLICATE KEY UPDATE;
That can only work if the row index was UNIQUE:
CREATE TABLE IF NOT EXISTS `table` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`foo` int(10) unsigned NOT NULL,
`bar` int(10) unsigned NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `row` (`foo`,`bar`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
Otherwise, why have just an index?
Also the ON DUPLICATE KEY clauses allows you to update non-indexed columns.
As for REPLACE, keep in mind that REPLACE is actually DELETE and INSERT under the hood.