Difference between Insert into Select into SQL Server

In SQL Server, the INSERT INTO and SELECT INTO statements are used for inserting data, but they serve different purposes and have distinct behaviors. Here’s a breakdown of the differences:

INSERT INTO

• Purpose: The INSERT INTO statement is used to add existing records from one table into another table. The target table must already exist before you can use this statement.

Syntax:

INSERT INTO TargetTable (Column1, Column2)
 SELECT Column1, Column2
 FROM SourceTable
 WHERE Condition;

• Requires that the destination table already exists.
• You can specify which columns to insert data into.
• Can insert multiple rows from a select query.

SELECT INTO

Purpose: The SELECT INTO statement creates a new table and inserts the result of a query into that new table. This is often used for creating backup tables or for creating temporary tables based on existing data.

Syntax:

SELECT Column1, Column2
 INTO NewTable
 FROM SourceTable
 WHERE Condition;

• Creates a new table (if it does not already exist).
• Copies the structure and data from the source table into the new table.
• The new table’s column names and data types are derived from the selected columns of the source table.

Key Differences

1. Table Existence:
   • INSERT INTO: Requires the destination table to exist.
   • SELECT INTO: Creates a new table if it does not exist.
2. Use Case:
   • INSERT INTO: Used to add data to an existing table.
   • SELECT INTO: Used to create a new table and populate it with data.
3. Data Handling:
   • INSERT INTO: Can insert data into specific columns of an existing table.
   • SELECT INTO: Copies both structure and data into a new table.