ENVIRONMENT VARIABLES IN PostgreSQL: These are useful to avoid hard-coding database connection information into simple client applications, for example. To start a PostgreSQL server, you can run the following command:
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[postgres@postgres1 ~]$ /usr/local/pgsql/bin/pg_ctl –D /u01/data start |
However, you can also use an environmental variable to create a shortcut for this… Read More
CLUSTER AND MULTICLUSTERS IN POSTGRESQL: In PostgreSQL Before you can start a PostgreSQL server, you need to create a cluster. A cluster refers to a collection of databases managed by a single instance of the PostgreSQL server. When you install PostgreSQL, It doesn’t automatically create… Read More
Clauses and filters: Like clause:
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college=# select * from report where temp_hi:: text like '4%'; place | temp_lo | temp_hi | date | humidity | precp ----------------------------------------------------------- VZG | 32 | 43 | 2023-05-10 | 21 | HYD | 32 | 43 | 2020-07-19 | 24 | BZA | 32 | 43 | 2023-05-09 | 23 | (3 rows) |
LIMIT Clause: The LIMIT clause is used to restrict the number of rows returned in the result set. It is useful when you want to retrieve only a certain number of rows.
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college=# select * from report LIMIT 4; place | temp_lo | temp_hi | date | humidity | precp ----------------------------------------------------------- VZG | 32 | 43 | 2023-05-10 | 21 | HYD | 32 | 43 | 2020-07-19 | 24 | BZA | 32 | 43 | 2023-05-09 | 23 | Delhi | 23 | 34 | 2023-05-15 | 24 | (4 rows) |
OFFSET Clause: It is used in conjunction… Read More
JOIN OPERATION IN PostgreSQL: In PostgreSQL, the JOIN clause is used to combine rows from two or more tables based on a related column or condition. It specifies how the tables should be joined and on which columns the join should be performed. There are… Read More
In PostgreSQL, “ALTER” and “UPDATE” are two different SQL commands used to modify data in a database. “ALTER” is used to modify the structure of the database, while “UPDATE” is used to modify the data stored within the database. Update: The UPDATE command plays a… Read More
CREATING A NEW TABLE You can create a new table by specifying the table name, along with all column names and their types. Syntax for table creation: CREATE TABLE table_name( column1 datatype, column2 datatype, column3 datatype, columnN datatype, PRIMARY KEY (one or more columns) ); An example for creating table on weather… Read More
Installation of PostgreSQL Linux using Source Code: To begin, connect to the Linux virtual Machine via PuTTY using IP address. To obtain the IP address, log into the virtual machine and enter the command ‘ifconfig’ in the terminal. Now open Putty and enter the IP… Read More
Introduction to PostgreSQL • PostgreSQL (pronounced as post-gress-Q-L) is a high demand open-source object relational database management system (ORDBMS). It was developed by a worldwide team of volunteers. It is not controlled by any private entity so, it is available for free. • PostgreSQL uses… Read More
PostgreSQL Articles Dear Readers, Please check the below list of PostgreSQL Articles SNo Description Link 1 Installation of PostgreSQL 11.4 On Windows Platform https://www.ktexperts.com/installation-of-postgresql-11-4-on-windows-platform/ 2 How to Download and Install the pgAdmin 4 https://www.ktexperts.com/how-to-download-and-install-the-pgadmin-4/ 3 Installation of PostgreSQL 11.4 in Linux Platform. https://www.ktexperts.com/installation-of-postgresql-11-4-in-linux-platform/ 4 Install… Read More
