COPY TO

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Overview

The COPY TO statement is used to export tables, specific columns, or results of select queries into .csv files. It allows you to copy data from a table or query result and save it to a specified file.

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Syntax

The syntax for COPY TO is as follows:

COPY { table_name [ ( column_name [, ...] ) ] | ( query ) } TO 'filename' [( option [, ...] ) ];

Parameters in the syntax include:

• table_name: Table with the data to export.

• column_name: Optional. Specify columns for export.

• query: A SELECT statement for exporting specific results.

• filename: File name for saving the exported data.

• option: Optional parameters for customization.

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Example

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Step #1: Create a Table

1. Before creating The table, check for duplicate tables using the following statement:

DESCRIBE DATABASE

2. You will receive a list of existing tables in Oxla:

 namespace_name |      name      
----------------+----------------
 public         | client
 public         | distance_table
 public         | weight
 public         | product

3. Now, let’s create a table for exporting data to a CSV file. Here, we’ll create a ”salary” table:

CREATE TABLE salary (
  empid int,
  empname string,
  empdept string,
  empaddress string,
  empsalary int
);
INSERT INTO salary 
    (empid, empname, empdept, empaddress, empsalary) 
VALUES 
    (2001,'Paul','HR', 'California', null ),
    (2002,'Brandon','Product', 'Norway', 15000),
    (2003,'Bradley','Marketing', 'Texas', null),
    (2004,'Lisa','Marketing', 'Houston', 10000),
    (2005,'Emily','Marketing', 'Texas', 20000),
    (2006,'Bobby','Finance', 'Seattle', 20000),
    (2007,'Parker','Project', 'Texas', 45000);

4. The table and data were created successfully.

COMPLETE
INSERT 0 7

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Step #2: Copy the Table into the CSV File

Option 1: Exporting all columns from a table

Copy all columns in the table to the specified CSV file:

COPY salary TO '/path/to/exportsalary.csv';

You will get the following successful result:

--
(0 rows)

The data from the table will be exported to the CSV file.

Option 2: Exporting specific columns from a table

Copy only specific columns by specifying the column names in the query:

COPY salary (empid, empname, empsalary) TO 'exportsalary.csv';

You will get the following successful result:

--
(0 rows)

The data from the specified columns will be exported to the CSV file.

Option 3: Exporting results of a SELECT statement

In the example below, copy data only from the Marketing department using the SELECT statement and WHERE clause:

COPY (SELECT * FROM salary WHERE empdept = 'Marketing') TO 'exportsalary.csv';

You will get the following successful result:

--
(0 rows)

Data exported to CSV file is only from the Marketing department.