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In this tutorial, we aim to explore how to set NULL the value in MySQL. If there is no value, then the specific table field in MySQL has to be updated NULL . This NULL value addition helps in data storage, accessibility, and analysis. You m...

This tutorial explains the refresh permissions operation and its implementation with examples. Implementing refresh permissions in MySQL MySQL implements user management through grant tables to ensure security and access control in the serv...

This tutorial shows you how to reset the auto increment in a MySQL table. Most businesses and organizations using MySQL need to insert values ​​into multiple tables simultaneously. While it is not possible to make all fields of the inse...

In this article, we will discuss the different types of ranges in PostgreSQL. Range types in PostgreSQL By default, Postgres provides some ranges to compare these values. Postgres has a daterange date type to compare dates. Also, we can use...

IN Today, we will take a closer look at how the and ANY operators work in PostgreSQL . However, remember that both are standard SQL operators, which means we can use them on multiple management platforms. By looking at them one by one and t...

This article will introduce PostgreSQL INSERT ON DUPLICATE UPDATE . 插入重复更新 What does it mean? Why should I use it? Whenever you add 插入 a record to the table, you add 主键 a data set with a unique ID. It can be a different...

Last time, we read about how to use it in PostgreSQL UPSERT . In a quick review, UPSERT is short for , which tends to insert values ​​into the table INSERT ON DUPLICATE UPDATE if they don't match a previous entry . If they do, they are...

ON DELETE CASCADE Before we start looking at different solutions for implementing in PostgreSQL , we will first understand ON DELETE CASCADE what is and what it does. Let's assume you have two tables, one of which inherits from a parent tab...

In our article, we mainly work on the PostgreSQL application called pgAdmin [app. number] , which can be downloaded from the PostgreSQL website. Therefore, we hope that you already have the application installed or another alternative where...

A VALUES in MySQL Auto_Increment is an auto-incrementing variable that helps provide a unique identification for a set of data in a table. It is most commonly used PRIMARY in a key to uniquely index a row. In MySQL, we can AUTO INCREMENT ap...

The PostgreSQL official documentation states, ``LATERAL 关键字可以位于子 SELECT FROM 项之前。这允许子 SELECT 引用出现在 FROM 中的 FROM 项的列（如果没有 LATERAL ，每个子 SELECT 都是独立评估的，因此不...

USERNAME Many PostgreSQL users may be asked for their database settings for the first time when logging in PASSWORD . However, just learning these settings is not all you need to know. What is the server in Rails 4? The server in Rails 4 us...

PSQL is a terminal-based front-end for the PostgreSQL database server. It uses either command-line arguments from an input file or from the command line, and is portable and easy to use. It also helps in writing scripts and letting other ta...

Before we start looking at different solutions to this problem, let's understand what a CSV file is and how output works in PL/pgSQL. PL/pgSQL output is the data displayed after running certain types of queries in PostgreSQL. Sometimes, as...

Let's start with a simple question. INFORMATION_SCHEMA What exactly is it? INFORMATION_SCHEMA Provides us with information about the objects defined in our database. It contains a set VIEWS of objects that store QUERY the database objects....