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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....

This article will use the PostgreSQL database to show the different commands we can use to return a collection of database tables. MySQL A common command you will encounter in databases is , SHOW TABLES but in PostgreSQL, the database manag...

In this article, we will introduce MySQL comments. We will also understand what type of comments should be used and where. Comments are written to describe the code and make it easier to understand. We also use comments to ignore a part of...

Today, we will learn 等待表元数据锁定 . This article focuses on the causes of metadata lock waits and provides solutions. What are locks in MySQL? A lock is a mechanism associated with a table to restrict unauthorized access to the...

In some cases, users want to capture the operations in an output file or some local storage. The storage can be a CSV file or a notepad where the contents of the SQL can be placed. outfile This file is generated using the MySQL command. Thi...

Traditional SQL INSERT statements do not perform input validation of their parameters/values ​​against existing database tables, which sometimes results in errors when duplicate keys are found during the insert process. This is handled...

This tutorial aims to understand unsigned in MySQL. unsigned Using keywords in MySQL Businesses and organizations have to assign data type as unsigned for certain columns. However, it is important to understand when and where to use this da...

Summary: in this tutorial, we will learn how to shuffle or sort the values ​​or records of a table in MySQL. Most businesses and organizations that use MySQL for data analysis or visualization need to sort different table values ​​o...

In this tutorial article, we will explain how to declare variables in SQL code for MySQL database. In SQL scripts, you can use variables to store values ​​and use them in place of literals during the execution of a series of commands. U...

When we develop applications, we end up hosting them with the desired cloud providers under specific monthly or annual subscriptions. Depending on your plan, these subscriptions provide us with different services like data stored in databas...

Unlike SQL Server, PostgreSQL does not have a built-in DATEDIFF function to calculate the difference between dates. However, you can use expressions that include other functions provided by PostgreSQL to obtain the difference between dates....

In this tutorial, we will learn how to insert data from a database hosted on a remote server into a database in our local computer. We will use the remote service provider Heroku PostgreSQL, which offers a free plan for testing purposes. In...

PostgreSQL provides many functions and operators for built-in data types. This tutorial will give an example of extracting the date from a timestamp in PostgreSQL or Postgres. CAST Extracting the date from a timestamp using the operator in...

In this article, we will learn how DATEFIELD to find the day of the week from a given in the table in PostgreSQL. We will also learn about different operations that you can use to manipulate and work with DATEFIELD the data in . We use EXTR...

Before we begin, let's define what a timestamp is in SQL. From the PostgreSQL documentation under the DATE/TIME heading, a timestamp is a data type that stores a date and time in the following format. YYYY-MM-DD hh:mm:ss (DATE | TIME) The s...