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December 16, 2015

12/16/2015 09:08:00 PM

The basic syntax for a CREATE TABLE is:
CREATE TABLE table_name(
column1 datatype null/not null,
column2 datatype null/not null,
...);
Each column must have a datatype. The column should either be defined as "null" or "not null" and if this value is left blank, the database assumes "null" as the default.
For example:

CREATE TABLE supplier(
supplier_id numeric(10) not null,
supplier_name varchar2(50) not null,
contact_name varchar2(50))
CREATE Table from another table

You can also create a table from an existing table by copying the existing table's columns. It is important to note that when creating a table in this way, the new table will be populated with the records from the existing table (based on the SELECT Statement).
Syntax #1 - Copying all columns from another table

CREATE TABLE new_table
AS (SELECT * FROM old_table);
For example:
CREATE TABLE suppliers
AS (SELECT *
FROM companies
WHERE id > 1000);
This would create a new table called suppliers that included all columns from the companies table.
If there were records in the companies table, then the new suppliers table would also contain the records selected by the SELECT statement.
Syntax #2 - Copying selected columns from another table

CREATE TABLE new_table
AS (SELECT column_1, column2, ... column_n FROM old_table);
For example:
CREATE TABLE suppliers
AS (SELECT id, address, city, state, zip
FROM companies
WHERE id > 1000);

This would create a new table called suppliers, but the new table would only include the specified columns from the companies table.
Again, if there were records in the companies table, then the new suppliers table would also contain the records selected by the SELECT statement.
Syntax #3 - Copying selected columns from multiple tables

CREATE TABLE new_table
AS (SELECT column_1, column2, ... column_n
FROM old_table_1, old_table_2, ... old_table_n);
For example:
CREATE TABLE suppliers
AS (SELECT companies.id, companies.address, categories.cat_type
FROM companies, categories
WHERE companies.id = categories.id
AND companies.id > 1000);
This would create a new table called suppliers based on columns from both the companies and categories tables.The basic syntax for a CREATE TABLE is:
CREATE TABLE table_name(
column1 datatype null/not null,
column2 datatype null/not null,
...);
Each column must have a datatype. The column should either be defined as "null" or "not null" and if this value is left blank, the database assumes "null" as the default.
For example:

CREATE TABLE supplier(
supplier_id numeric(10) not null,
supplier_name varchar2(50) not null,
contact_name varchar2(50))
CREATE Table from another table

You can also create a table from an existing table by copying the existing table's columns. It is important to note that when creating a table in this way, the new table will be populated with the records from the existing table (based on the SELECT Statement).
Syntax #1 - Copying all columns from another table

CREATE TABLE new_table
AS (SELECT * FROM old_table);
For example:
CREATE TABLE suppliers
AS (SELECT *
FROM companies
WHERE id > 1000);
This would create a new table called suppliers that included all columns from the companies table.
If there were records in the companies table, then the new suppliers table would also contain the records selected by the SELECT statement.
Syntax #2 - Copying selected columns from another table

CREATE TABLE new_table
AS (SELECT column_1, column2, ... column_n FROM old_table);
For example:
CREATE TABLE suppliers
AS (SELECT id, address, city, state, zip
FROM companies
WHERE id > 1000);

This would create a new table called suppliers, but the new table would only include the specified columns from the companies table.
Again, if there were records in the companies table, then the new suppliers table would also contain the records selected by the SELECT statement.
Syntax #3 - Copying selected columns from multiple tables

CREATE TABLE new_table
AS (SELECT column_1, column2, ... column_n
FROM old_table_1, old_table_2, ... old_table_n);
For example:
CREATE TABLE suppliers
AS (SELECT companies.id, companies.address, categories.cat_type
FROM companies, categories
WHERE companies.id = categories.id
AND companies.id > 1000);
This would create a new table called suppliers based on columns from both the companies and categories tables.

 
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