Category: Databases

Run the following command: alter table TABLE_NAME alter column COLUMN_NAME type character varying(120); This will extend the character varying column field size to 120. Remember to change TABLE_NAME to the relevant table name...

If you need to copy data from one table (table_a) into another table (table_b) using pgsql. There are 2 methods on how to do this. Method 1 NOTE: If you are using this method table_b should not yet exist. If you want an exact...

How to copy a columns data from one table into a column in another table using PostgreSQL? Eg. name columns data from the users table into namecolumn in the new_users table. Execute the query below with different column names...

Run the following query: SELECT version(); The result will look as below:                                                version...

How to create a backup of a PostgreSQL database to a sql file? This sql file then can be used to restore the database on a later stage. Follow the steps below in order to create a backup Open a Terminal Window if not yet...

Use the DISTINCT ON keyword in your query To do a case-insensitive search do the following query SELECT DISTINCT ON(upper(surname)) surname FROM employees ORDER BY upper(surname) This will return non-duplicate surnames....

Type in the following command in postgres using the command line: copy products from ‘/home/user/products.csv’ using delimiters ‘,’ products = (Database Table) ‘/home/user/products.csv‘...

Type in the following command in postgres using the command line: copy products to ‘/home/user/products.csv’ delimiters ‘,’ CSV HEADER products = (Database Table) ‘/home/user/products.csv‘...

Type in the following command in postgres using the command line: copy products to ‘/home/user/products.csv’ delimiters ‘,’ products = (Database Table) ‘/home/user/products.csv‘ = (Location...

Editing the pg_hba.conf file on a postgresql database server so that a specific (other) server will be able to connect to the postgresql database server. Example: Say I have a server where all of my postgresql databases are...