Can you explain the SELECT INTO Statement

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SELECT INTO statement is used mostly to create backups. The below SQL backsup the Employee table in to the EmployeeBackUp table. One point to be noted is that the structure of pcdsEmployeeBackup and pcdsEmployee table should be same. SELECT * INTO pcdsEmployeeBackup FROM pcdsEmployee.

Certainly! The SELECT INTO statement in a database management system (DBMS) is used to create a new table based on the result set returned by a SELECT query. Here’s how it works:

  1. SELECT Query: First, you write a SELECT query to retrieve data from one or more tables in the database. This query can include various conditions, joins, and other clauses to filter or manipulate the data as needed.
  2. INTO Clause: After the SELECT statement, you add an INTO clause followed by the name of the new table you want to create. This is where the result set of the SELECT query will be stored.
  3. Execution: When you execute the SELECT INTO statement, the DBMS executes the SELECT query and creates a new table with the specified name. The structure of the new table (columns and their data types) is determined by the columns selected in the SELECT query.
  4. Data Population: The data from the result set of the SELECT query is then inserted into the newly created table. Each row in the result set becomes a row in the new table.

Here’s a simple example to illustrate:

sql
SELECT column1, column2
INTO new_table
FROM existing_table
WHERE condition;

In this example:

  • column1 and column2 are columns from the existing_table that you want to select data from.
  • new_table is the name of the new table that will be created.
  • The WHERE clause is optional and is used to specify any conditions to filter the rows selected from the existing_table.

After executing this statement, a new table named new_table will be created, containing the columns column1 and column2, and populated with the data retrieved from the existing_table based on the specified conditions.

It’s important to note that the SELECT INTO statement is often used to create temporary or intermediate tables for data manipulation or analysis purposes, as the newly created table does not already exist in the database schema prior to execution.