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What is the concept of CTAS (CREATE TABLE AS SELECTED) in MySQL?
CTAS i.e. “Create Table AS Select” script is used to create a table from an existing table. It copies the table structure as well as data from the existing table. Consider the following example in which we have created a table named EMP_BACKUP from an already existing table named ‘Employee’
mysql> Select * from Employee; +------+--------+ | Id | Name | +------+--------+ | 100 | Ram | | 200 | Gaurav | | 300 | Mohan | +------+--------+ 3 rows in set (0.00 sec)
The query above shows the data in table ’Employee’ and the query below will create the table named ‘EMP_BACKUP’ by copying the structure as well as data from the ‘Employee’ table.
mysql> Create table EMP_BACKUP AS SELECT * from EMPLOYEE; Query OK, 3 rows affected (0.15 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> Select * from EMP_BACKUP; +------+--------+ | Id | Name | +------+--------+ | 100 | Ram | | 200 | Gaurav | | 300 | Mohan | +------+--------+ 3 rows in set (0.00 sec)
We can observe that it copied all the data and structure of the ‘Employee’ table.
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