- PostgreSQL - Home
- PostgreSQL - Overview
- PostgreSQL - Environment Setup
- PostgreSQL - Syntax
- PostgreSQL - Data Types
- PostgreSQL - Operators
- PostgreSQL - Expressions
- PostgreSQL Database
- PostgreSQL - Create Database
- PostgreSQL - ALTER DATABASE
- PostgreSQL - Drop Database
- PostgreSQL - Loading Database
- PostgreSQL - Rename Database
- PostgreSQL - Select Database
- PostgreSQL - Show Database
- PostgreSQL Query Operations
- PostgreSQL - SELECT
- PostgreSQL - CREATE
- PostgreSQL - INSERT
- PostgreSQL - UPDATE
- PostgreSQL - DELETE
- PostgreSQL - ALTER TABLE Command
- PostgreSQL - WHERE Clause
- PostgreSQL - ORDER BY Clause
- PostgreSQL - GROUP BY
- PostgreSQL - HAVING Clause
- PostgreSQL - DISTINCT Keyword
- PostgreSQL - LIMIT Clause
- PostgreSQL - LIKE Clause
- PostgreSQL - WITH Clause
- PostgreSQL - AND & OR Clauses
- PostgreSQL - DROP TABLE
- PostgreSQL - Upsert
- TRUNCATE TABLE Command
- PostgreSQL JOINS & Schemas
- PostgreSQL Schemas
- PostgreSQL Joins
- PostgreSQL Data Integrity & Transaction
- PostgreSQL - Constraints
- PostgreSQL - Transactions
- PostgreSQL - Commit
- PostgreSQL - Rollback
- PostgreSQL - Views
- PostgreSQL Functions
- PostgreSQL - ALIAS Syntax
- PostgreSQL - Functions
- PostgreSQL - Useful Function
- PostgreSQL - MAX() Function
- PostgreSQL - MIN() Function
- PostgreSQL - SUM() Function
- PostgreSQL - COUNT() Function
- PostgreSQL - Array Function
- PostgreSQL - String Function
- PostgreSQL - Numeric Function
- PostgreSQL Operators
- PostgreSQL - UNION Operator
- PostgreSQL - INTERSECT Operator
- PostgreSQL - EXCEPT Operator
- PostgreSQL - ANY Operator
- PostgreSQL - ALL Operator
- PostgreSQL - EXISTS Operator
- PostgreSQL Interface
- PostgreSQL - C / C++
- PostgreSQL - Java
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- Advanced PostgreSQL
- PostgreSQL - NULL Values
- PostgreSQL - Triggers
- PostgreSQL - Indexes
- PostgreSQL - Locks
- PostgreSQL - Sub Queries
- PostgreSQL - Auto Increment
- PostgreSQL - Privileges
- PostgreSQL - Date/Time Functions & Operators
- PostgreSQL - Errors & Messages
- PostgreSQL - Assert
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.