
- PostgreSQL Tutorial
- PostgreSQL - Home
- PostgreSQL - Overview
- PostgreSQL - Environment Setup
- PostgreSQL - Syntax
- PostgreSQL - Data Types
- PostgreSQL - Create Database
- PostgreSQL - Select Database
- PostgreSQL - Drop Database
- PostgreSQL - Create Table
- PostgreSQL - Drop Table
- PostgreSQL - Schema
- PostgreSQL - Insert Query
- PostgreSQL - Select Query
- PostgreSQL - Operators
- PostgreSQL - Expressions
- PostgreSQL - Where Clause
- PostgreSQL - AND & OR Clauses
- PostgreSQL - Update Query
- PostgreSQL - Delete Query
- PostgreSQL - Like Clause
- PostgreSQL - Limit Clause
- PostgreSQL - Order By Clause
- PostgreSQL - Group By
- PostgreSQL - With Clause
- PostgreSQL - Having Clause
- PostgreSQL - Distinct Keyword
- Advanced PostgreSQL
- PostgreSQL - Constraints
- PostgreSQL - Joins
- PostgreSQL - Unions Clause
- PostgreSQL - NULL Values
- PostgreSQL - Alias Syntax
- PostgreSQL - Triggers
- PostgreSQL - Indexes
- PostgreSQL - Alter Table Command
- Truncate Table Command
- PostgreSQL - Views
- PostgreSQL - Transactions
- PostgreSQL - Locks
- PostgreSQL - Sub Queries
- PostgreSQL - Auto Increment
- PostgreSQL - Privileges
- Date/Time Functions & Operators
- PostgreSQL - Functions
- PostgreSQL - Useful Functions
- PostgreSQL Interfaces
- PostgreSQL - C/C++
- PostgreSQL - Java
- PostgreSQL - PHP
- PostgreSQL - Perl
- PostgreSQL - Python
- PostgreSQL Useful Resources
- PostgreSQL - Quick Guide
- PostgreSQL - Useful Resources
- PostgreSQL - Discussion
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- UPSC IAS Exams Notes
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PostgreSQL - SELECT Database
This chapter explains various methods of accessing the database. Assume that we have already created a database in our previous chapter. You can select the database using either of the following methods −
- Database SQL Prompt
- OS Command Prompt
Database SQL Prompt
Assume you have already launched your PostgreSQL client and you have landed at the following SQL prompt −
postgres=#
You can check the available database list using \l, i.e., backslash el command as follows −
postgres-# \l List of databases Name | Owner | Encoding | Collate | Ctype | Access privileges -----------+----------+----------+---------+-------+----------------------- postgres | postgres | UTF8 | C | C | template0 | postgres | UTF8 | C | C | =c/postgres + | | | | | postgres=CTc/postgres template1 | postgres | UTF8 | C | C | =c/postgres + | | | | | postgres=CTc/postgres testdb | postgres | UTF8 | C | C | (4 rows) postgres-#
Now, type the following command to connect/select a desired database; here, we will connect to the testdb database.
postgres=# \c testdb; psql (9.2.4) Type "help" for help. You are now connected to database "testdb" as user "postgres". testdb=#
OS Command Prompt
You can select your database from the command prompt itself at the time when you login to your database. Following is a simple example −
psql -h localhost -p 5432 -U postgress testdb Password for user postgress: **** psql (9.2.4) Type "help" for help. You are now connected to database "testdb" as user "postgres". testdb=#
You are now logged into PostgreSQL testdb and ready to execute your commands inside testdb. To exit from the database, you can use the command \q.