SQL | Create Table Extension

Table Extensions in Context of ERP/CRM Systems: In some systems, such as Microsoft Dynamics 365 Business Central (previously known as Dynamics NAV), "table extensions" allow developers to add additional fields to existing tables without modifying them directly. This approach provides an extension model that avoids altering the core system tables.
CREATE TABLE ... AS: This is a way to create a new table based on the result set of a SELECT statement.
Syntax:
```
CREATE TABLE new_table AS
SELECT columns
FROM existing_table
WHERE conditions;
```
Example:
```
CREATE TABLE new_employees AS
SELECT FirstName, LastName
FROM employees
WHERE hire_date > '2022-01-01';
```
This will create a new_employees table with the same structure as the result set of the SELECT statement.
Inheriting Tables in PostgreSQL: PostgreSQL offers table inheritance, which allows for a table to be created as an "extension" or child of an existing table, inheriting its columns.
Syntax:
```
CREATE TABLE new_table ( 
   ... new columns ...
) INHERITS (existing_table);
```
Example:
```
CREATE TABLE extended_employees (
   hire_date DATE
) INHERITS (employees);
```
Here, extended_employees will have all columns from employees plus the hire_date column.

If you're referring to a specific concept or feature in a certain system or context, please provide more details. If one of the mentioned interpretations fits what you're looking for, then that's great! Otherwise, clarifying your requirement can help in providing a more accurate explanation or solution.

Advanced Table Creation Features in SQL:
- Advanced table creation features may include specifying storage parameters, table compression, and advanced indexing options.
```
CREATE TABLE your_table (
   column1 INT,
   column2 VARCHAR(50)
) TABLESPACE your_tablespace COMPRESS;
```
Database-Specific Table Creation Enhancements:
- Different databases offer unique features. For example, in Oracle, you can use the ENABLE ROW MOVEMENT clause to allow rows to be moved.
```
CREATE TABLE your_table (
   column1 INT,
   column2 VARCHAR(50)
) ENABLE ROW MOVEMENT;
```
SQL CREATE TABLE Options and Extensions:
- Some databases provide options for creating temporary tables, global temporary tables, or specifying parallel execution for table creation.
```
CREATE GLOBAL TEMPORARY TABLE your_temp_table (
   column1 INT,
   column2 VARCHAR(50)
) ON COMMIT PRESERVE ROWS;
```

Innovative SQL Table Creation Techniques:

Using partitioning to improve query performance and data management.

CREATE TABLE your_partitioned_table (
   column1 INT,
   column2 VARCHAR(50)
) PARTITION BY RANGE (column1) (
   PARTITION p1 VALUES LESS THAN (100),
   PARTITION p2 VALUES LESS THAN (MAXVALUE)
);

Extending CREATE TABLE Functionality in SQL:
- Leveraging features like table compression, in-memory tables, or sharding for scalability.
```
CREATE TABLE your_table (
   column1 INT,
   column2 VARCHAR(50)
) INMEMORY COMPRESS FOR QUERY HIGH;
```
Database-Specific Table Creation Extensions:
- Each database system may have unique extensions. For example, in PostgreSQL, you can use the WITH OIDS option.
```
CREATE TABLE your_table (
   column1 INT,
   column2 VARCHAR(50)
) WITH OIDS;
```
Advanced Table Definition in SQL:
- Defining complex types, arrays, or JSON columns for advanced data structures.
```
CREATE TABLE your_table (
   column1 INT,
   column2 JSON
);
```