Postgres and Open Source Experts

This post demonstrates stepwise instructions for importing CSV to Postgres or exporting Postgres tables to CSV files using pgAdmin.

PostgreSQL allows us to import CSV files to Postgres tables or export Postgres tables to CSV files using SQL Shell (psql). To do that, the “\COPY” command is used.

Postgres provides an INNER JOIN clause to combine the records of multiple tables based on a specific condition/criteria.

Postgres provides a couple of ways to drop all the tables of a Postgres database, such as dropping the complete schema or removing the schema’s tables individually.

In PostgreSQL, the COALESCE() function and the IS NULL operator are used to find and replace the null values with some default values.

The INTERVAL keyword is used to define an interval in Postgres. This blog explained the usage of the INTERVAL data type in Postgres via suitable examples.

The ALTER TABLE command in PostgreSQL is used to alter the tables' structure, such as adding columns, renaming columns/tables, dropping columns, modifying constraints, etc.

In Postgres, the standard “information_schema”, a system catalog table named “pg_namespace”, and the “\dn” command is used to get the list of available schemas.

PostgreSQL provides different built-in commands and queries to get the list of all the tables, such as the “\dt” command, “pg_tables”, “information_schema”, etc.

In Postgres, the IS NULL operator tests whether an expression/column contains a null value. It can be used with different statements, such as SELECT, UPDATE, etc.