PostgreSQL Create Table: Create a table countries, including columns which already exist

2. Write a SQL statement to create a simple table countries, including columns country_id,country_name and region_id which already exist.

Sample Solution:

Code:

-- This SQL statement creates a new table called 'countries' with specified columns.

CREATE TABLE countries (
    COUNTRY_ID varchar(3), -- Defines a column 'COUNTRY_ID' to store country IDs as strings with a maximum length of 3 characters.
    COUNTRY_NAME varchar(45), -- Defines a column 'COUNTRY_NAME' to store country names as strings with a maximum length of 45 characters.
    REGION_ID decimal(10,0) -- Defines a column 'REGION_ID' to store region IDs as decimal numbers with a precision of 10 digits and no decimal places.
);

Explanation:

• The CREATE TABLE statement is used to create a new table in the database.
• The table is named 'countries'.
• Inside the parentheses, each line specifies a column in the table along with its data type and optional constraints.
• varchar(3) indicates a variable-length character string with a maximum length of 3 characters for the 'COUNTRY_ID' column.
• varchar(45) indicates a variable-length character string with a maximum length of 45 characters for the 'COUNTRY_NAME' column.
• decimal(10,0) indicates a decimal number with a precision of 10 digits and no decimal places for the 'REGION_ID' column.
• Each column definition is separated by a comma.

Output:

Here is the output for the above SQL statement. The following output shows an error message, because the table already exists.

postgres=# CREATE TABLE countries (
postgres(# COUNTRY_ID varchar(3),
postgres(# COUNTRY_NAME varchar(45),
postgres(# REGION_ID decimal(10,0)
postgres(# );
ERROR:  relation "countries" already exists

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