In MySQL, can I copy one row to insert into the sa

Question

insert into table select * from table where primarykey=1

I just want to copy one row to insert into the same table (i.e., I want to duplicate an existing row in the table) but I want to do this without having to list all the columns after the "select", because this table has too many columns.

But when I do this, I get the error:

Duplicate entry 'xxx' for key 1

I can handle this by creating another table with the same columns as a temporary container for the record I want to copy:

create table oldtable_temp like oldtable;
insert into oldtable_temp select * from oldtable where key=1;
update oldtable_tem set key=2;
insert into oldtable select * from oldtable where key=2;

Is there a simpler way to solve this?

Answer 1

I'm assuming you want the new record to have a new primarykey? If primarykey is AUTO_INCREMENT then just do this:

INSERT INTO table (col1, col2, col3, ...)
SELECT col1, col2, col3, ... FROM table
  WHERE primarykey = 1

...where col1, col2, col3, ... is all of the columns in the table except for primarykey.

If it's not an AUTO_INCREMENT column and you want to be able to choose the new value for primarykey it's similar:

INSERT INTO table (primarykey, col2, col3, ...)
SELECT 567, col2, col3, ... FROM table
  WHERE primarykey = 1

...where 567 is the new value for primarykey.

Answer 2

For a very simple solution, you could use PHPMyAdmin to export the row as a CSV file then simply import the amended CSV file. Editing the ID/primarykey column to show no value before you import it.

SELECT * FROM table where primarykey=1

Then at the bottom of the page:

Where is says "Export" simply export, then edit the csv file to remove the primarykey value, so it's empty, and then just import it into the database, a new primarykey will be assigned on import.

Answer 3

You could also try dumping the table, finding the insert command and editing it:

mysqldump -umyuser -p mydatabase --skip-extended-insert mytable > outfile.sql

The --skip-extended-insert gives you one insert command per row. You may then find the row in your favourite text editor, extract the command and alter the primary key to "default".

Answer 4

If your table's primary key field is an auto increment field, then you can use query with columns. For example, your table named test_tbl has 3 fields as id, name, age. id is a primary key field and auto increment, so you can use the following query to duplicate the row:

INSERT INTO `test_tbl` (`name`,`age`) SELECT `name`,`age` FROM `test_tbl`;

This query results in duplicating every row.

---

If your table's primary key field is not an auto increment field, then you can use the following method:

INSERT INTO `test_tbl` (`id`,`name`,`age`)
  SELECT 20,`name`,`age` FROM `test_tbl` WHERE id = 19;

The result of this query is a duplicate row of id=19 inserted as id=20.

Answer 5

I might be late in this, but I have a similar solution which has worked for me.

 INSERT INTO `orders` SELECT MAX(`order_id`)+1,`container_id`, `order_date`, `receive_date`, `timestamp` FROM `orders` WHERE `order_id` = 1

This way I don't need to create a temporary table and etc. As the row is copied in the same table the Max(PK)+1 function can be used easily.

I came looking for the solution of this question (had forgotten the syntax) and I ended up making my own query. Funny how things work out some times.

Regards

Answer 6

This procedure assumes that:

• you don't have _duplicate_temp_table
• your primary key is int
• you have access to create table

Of course this is not perfect, but in certain (probably most) cases it will work.

DELIMITER $$
CREATE PROCEDURE DUPLICATE_ROW(copytable VARCHAR(255), primarykey VARCHAR(255), copyid INT, out newid INT)
BEGIN
        DECLARE EXIT HANDLER FOR SQLEXCEPTION SET @error=1;
        SET @temptable = '_duplicate_temp_table';
        SET @sql_text = CONCAT('CREATE TABLE ', @temptable, ' LIKE ', copytable);
        PREPARE stmt FROM @sql_text;
        EXECUTE stmt;
        DEALLOCATE PREPARE stmt;
        SET @sql_text = CONCAT('INSERT INTO ', @temptable, ' SELECT * FROM ', copytable, ' where ', primarykey,'=', copyid);
        PREPARE stmt FROM @sql_text;
        EXECUTE stmt;
        DEALLOCATE PREPARE stmt;
        SET @sql_text = CONCAT('SELECT max(', primarykey, ')+1 FROM ', copytable, ' INTO @newid');
        PREPARE stmt FROM @sql_text;
        EXECUTE stmt;
        DEALLOCATE PREPARE stmt;
        SET @sql_text = CONCAT('UPDATE ', @temptable, ' SET ', primarykey, '=@newid');
        PREPARE stmt FROM @sql_text;
        EXECUTE stmt;
        DEALLOCATE PREPARE stmt;
        SET @sql_text = CONCAT('INSERT INTO ', copytable, ' SELECT * FROM ', @temptable, '');
        PREPARE stmt FROM @sql_text;
        EXECUTE stmt;
        DEALLOCATE PREPARE stmt;
        SET @sql_text = CONCAT('DROP TABLE ', @temptable);
        PREPARE stmt FROM @sql_text;
        EXECUTE stmt;
        DEALLOCATE PREPARE stmt;
        SELECT @newid INTO newid;
END $$
DELIMITER ;

CALL DUPLICATE_ROW('table', 'primarykey', 1, @duplicate_id);
SELECT @duplicate_id;