Khóa học miễn phí MySQL – Clone Tables nhận dự án làm có lương

MySQLi – Clone Tables



There may be a situation when you need an exact copy of a table and CREATE TABLE … SELECT doesn”t suit your purposes because the copy must include the same indexes, default values, and so forth.

You can handle this situation by following steps −

  • Use SHOW CREATE TABLE to get a CREATE TABLE statement that specifies the source table”s structure, indexes and all.

  • Modify the statement to change the table name to that of the clone table and execute the statement. This way, you will have exact clone table.

  • Optionally, if you need the table contents copied as well, issue an INSERT INTO … SELECT statement, too.

Example

Try out the following example to create a clone table for tutorials_inf.

Step 1

Get complete structure about table.

mysql> SHOW CREATE TABLE tutorials_inf G;
*************************** 1. row ***************************
       Table: tutorials_inf
Create Table: CREATE TABLE `tutorials_inf` (
   `id` int(11) NOT NULL,
   `name` varchar(20) NOT NULL,
   PRIMARY KEY (`id`),
   UNIQUE KEY `AUTHOR_INDEX` (`name`),
   UNIQUE KEY `NAME_INDEX` (`name`),
   KEY `id` (`id`)
) ENGINE = InnoDB DEFAULT CHARSET = latin1
1 row in set (0.05 sec)

ERROR: No query specified

Step 2

Rename this table and create another table.

mysql> CREATE TABLE tutorials_clone(
   → id int(11) NOT NULL,
   → name varchar(20) NOT NULL,
   → PRIMARY KEY (id),
   → UNIQUE KEY AUTHOR_INDEX (name),
   → UNIQUE KEY NAME_INDEX (name),
   →  KEY id (id));
Query OK, 0 rows affected (1.80 sec)

Step 3

After executing step 2, you will create a clone table in your database. If you want to copy data from old table then you can do it by using INSERT INTO… SELECT statement.

mysql> INSERT INTO tutorials_clone(id,name) SELECT id,name from tutorials_inf;
Query OK, 4 rows affected (0.19 sec)
Records: 4  Duplicates: 0  Warnings: 0

Finally, you will have exact clone table as you wanted to have.

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